How to uninstall a linux dual-boot system from your computer

Chris Hoffman is Editor-in-Chief of How-To Geek. He’s written about technology for over a decade and was a PCWorld columnist for two years. Chris has written for The New York Times, been interviewed as a technology expert on TV stations like Miami’s NBC 6, and had his work covered by news outlets like the BBC. Since 2011, Chris has written over 2,000 articles that have been read nearly one billion times—and that’s just here at How-To Geek. Read more.

Most computers ship with a single operating system, but you can have multiple operating systems installed on a single PC. Having two operating systems installed — and choosing between them at boot time — is known as “dual-booting.”

Google and Microsoft ended Intel’s plans for dual-boot Windows and Android PCs, but you can install Windows 8.1 alongside Windows 7, have both Linux and Windows on the same computer, or install Windows or Linux alongside Mac OS X.

How Dual-Booting Works

Your computer’s operating system is generally installed on its internal hard drive. When you boot your computer, the BIOS loads the boot loader from the hard drive and the boot loader boots the installed operating system.

There’s no limit to the number of operating systems you he installed — you’re not just limited to a single one. You could put a second hard drive into your computer and install an operating system to it, choosing which hard drive to boot in your BIOS or boot menu. You could also boot an operating system — like a live Linux system or a Windows To Go USB drive — from external storage media.

Even if you only have a single hard drive, you can have multiple operating systems on that hard drive. By partitioning the drive into several different partitions, you can have one partition for one operating system and another partition for another operating system, splitting the drive between them. (In reality, many operating systems use multiple partitions. The point is you’re devoting part of the drive to one operating system and part of the drive to another.)

When you install a Linux distribution, it typically installs the Grub boot loader. Grub loads instead of the Windows boot loader at boot time if Windows was already installed, allowing you to choose the operating system you want to boot. Windows also has its own boot loader, which can be used to select between different versions of Windows if you have more than one installed.

Why Bother Dual-Booting?

Different operating systems have different uses and advantages. Having more than one operating system installed allows you to quickly switch between two and have the best tool for the job. It also makes it easier to dabble and experiment with different operating systems.

For example, you could have both Linux and Windows installed, using Linux for development work and booting into Windows when you need to use Windows-only software or play a PC game. If you like Windows 7 but want to try out Windows 8.1, you could install Windows 8.1 alongside Windows 7 and choose between the two at boot time, knowing you’ll always be able to go back to Windows 7. If you’re using a Mac, you can have Windows installed alongside Mac OS X and boot into it when you need to run Windows-only software.

You could use virtual machine software instead of setting up a dual-boot system, but a dual-boot system lets you actually use both operating systems on your hardware at full, native speed. You don’t have to deal with the overhead of a virtual machine, which is especially bad when it comes to 3D graphics. The downside is you can only use one of your installed operating systems at a time.

Switching Between Operating Systems

If each operating system is installed to a separate drive, you could actually switch between both by selecting a different drive as your boot device every time you boot. This is inconvenient and you’ll probably have two operating systems installed on the same drive, so that’s where a boot manager comes in.

Switch between your installed operating systems by rebooting your computer and selecting the installed operating system you want to use. If you have multiple operating systems installed, you should see a menu when you start your computer. This menu is typically set up when you install an additional operating system on your computer, so you won’t see if you just have Windows installed or just have Linux installed.

Setting Up a Dual-Boot System

Setting up a dual-boot system is fairly easy. Here’s a quick overview of what to expect:

• Dual Boot Windows and Linux: Install Windows first if there’s no operating system installed on your PC. Create Linux installation media, boot into the Linux installer, and select the option to install Linux alongside Windows. Read more about setting up a dual-boot Linux system.
• Dual Boot Windows and Another Windows: Shrink your current Windows partition from inside Windows and create a new partition for the other version of Windows. Boot into the other Windows installer and select the partition you created. Read more about dual-booting two versions of Windows.
• Dual Boot Linux and Another Linux: You should be able to dual-boot two Linux distributions by installing one first and then installing the other. Choose to install the new Linux system alongside your old Linux system. Resize your old Linux partitions in the installer and create new ones to make space if the installer won’t do this autoamtically.
• Dual Boot Mac OS X and Windows: The Boot Camp utility included with Mac OS X allows you to easily set up a Windows dual-boot system on your Mac.
• Dual Boot Mac OS X and Linux: Boot Camp doesn’t allow you to set up a dual-boot Linux system, so you’ll need to do a bit more footwork here. Follow our guide to installing Linux on a Mac for more details.

You aren’t limited to just two operating systems on a single computer. If you wanted to, you could have three or more operating systems installed on your computer — you could have Windows, Mac OS X, and Linux all on the same computer. You’re only restricted by the storage space available on your computer and the time you want to spend setting this up.

Chris Hoffman is Editor-in-Chief of How-To Geek. He’s written about technology for over a decade and was a PCWorld columnist for two years. Chris has written for The New York Times, been interviewed as a technology expert on TV stations like Miami’s NBC 6, and had his work covered by news outlets like the BBC. Since 2011, Chris has written over 2,000 articles that have been read nearly one billion times—and that’s just here at How-To Geek. Read more.

Linux is often best installed in a dual-boot system. This allows you to run Linux on your actual hardware, but you can always reboot into Windows if you need to run Windows software or play PC games.

Setting up a Linux dual-boot system is fairly simple, and the principles are the same for every Linux distribution. Dual-booting Linux on a Mac or a Chromebook is a different process.

The Basics

Here’s the basic process you’ll need to follow:

• Install Windows First: If you already have Windows installed, that’s fine. If not, be sure to install Windows first, before you install the Linux system. If you install Linux second, it can set up its boot loader properly to happily co-exist with Windows. if you install Windows second, it will ignore Linux, and you’ll have to go through some trouble to get your Linux boot loader working again.
• Make Room for Linux: You’ll need free space on your Windows system drive to install Linux, or possibly a second entirely different hard drive if you have a desktop PC. You’ll usually need to resize your Windows partition to make room for Linux. If you’re installing Windows from scratch, be sure to leave some free space on the drive for Linux. This will save you some time later.
• Install Linux Second: Choose your Linux distribution and put its installer on a USB drive or DVD. Boot from that drive and install it on your system, making sure you select the option that installs it alongside Windows — don’t tell it to wipe your hard drive. It’ll automatically set up a Grub2 boot loader menu that lets you choose your preferred operating system each time you boot your computer.

Although the broad outlines are simple, this can be complicated by a number of issues including UEFI Secure Boot requirements on Windows 8 PCs and disk encryption.

Install Windows First

Your PC probably already has Windows installed on it, and that’s fine. If you’re setting up a PC from scratch, be sure to select the “Custom install” option and tell Windows to use only part of the hard drive, leaving some unallocated space left over for Linux. This will save you the trouble of resizing the partition later.

Make Room For Linux

You’ll probably want to resize your Windows system partition to make room for Linux. If you already have some unallocated space or a separate hard drive for Linux, that’s perfect. Otherwise, it’s time to resize that existing Windows partition so you can make space for a new Linux partition.

You can do this in several ways. Most Linux installers allow you to resize Windows NTFS partitions, so you can do this during the installation process. However, you may just want to shrink your Windows system partition from within Windows itself to avoid any potential problems.

To do so, open the Disk Management utility — press Windows Key + R, type diskmgmt.msc into the Run dialog, and press Enter. Right-click the Windows system partition — that’s likely your C:\ drive — and select “Shrink Volume.” Shrink it to free up space for your new Linux system.

If you’re using BitLocker encryption on Windows, you won’t be abne to resize the partition. Instead, you’ll need to open the Control Panel, access the BitLOcker settings page, and click the “Suspend protection” link to the right of the encrypted partition you want to resize. You can then resize it normally, and BitLocker will be re-enabled on the partition after you reboot your computer.

Install Linux Second

Next, make installation media for your Linux system. You can download an ISO file and burn it to a disk or create a bootable USB drive. Reboot your computer and it should automatically boot from the Linux installation media you’ve inserted. If not, you’ll need to change its boot order or use the UEFI boot menu to boot from a device.

On some newer PCs, your PC may refuse to boot from the Linux installation media because Secure Boot is enabled. Many Linux distributions will now boot normally on Secure Boot systems, but not all of them. You may need to disable Secure Boot before installing Linux.

Go through the installer until you reach an option that asks where (or how) you want to install the Linux distribution. This will look different depending on your Linux distribution, but you want to choose the option that lets you install Linux alongside Windows, or choose a manual partitioning option and create your own partitions. Don’t tell the installer to take over an entire hard drive or replace Windows, as that’ll wipe away your existing Windows system.

Choosing an Operating System and Customize Grub2

Once you’ve installed Linux, it will install the Grub2 boot loader to your system. Whenever you boot your computer, Grub2 will load first, allowing you to choose which operating system you want to boot — Windows or Linux.

You can customize Grub’s options, including which operating system is the default and how long Grub2 waits until it automatically boots that default operating system. Most Linux distributions don’t offer easy Grub2 configuration applications, so you may need to configure the Grub2 boot loader by editing its configuration files.

You can use this process to triple or quadruple-boot multiple versions of Linux along with Windows, multiple versions of Windows along with Linux, or multiple versions of each. Just install one after the other, ensuring there’s enough room for a separate partition for each operating system. Be sure to install Windows before you install Linux, too.

You may have installed Ubuntu or any other Linux distro on your PC alongside Windows 10. But maybe now if you don’t want to use Linux anymore. In this case, you will end up having a Linux partition on your hard drive that is taking up some disk space. In this post, we will show you how to safely uninstall Linux in Windows 10 dual boot without losing data or applications.

If you installed Ubuntu or a similar Linux distribution like Linux Mint with Wubi, you can easily uninstall the distro via the Programs and Features applet in Windows 10. Find Ubuntu in the list of installed programs, and then uninstall it like you would any other program. The uninstaller automatically removes the Ubuntu files and boot loader entry from your computer.

On the other hand, if you installed Linux to its own partition in a dual-boot configuration, uninstalling it requires removing the Linux partitions from your computer and then expanding your Windows partitions to use the now-free hard disk space.

Uninstall Linux in Windows 10 Dual Boot setup

This procedure is broken down into two parts, of which the first part is to remove the Linux operating system and the second part is to repair the Master Boot Record, as just deleting the Linux partition will result in a Grub rescue error.

Before you begin, you can back up your files and make sure you have a Windows 10 installation media handy. If you don’t have one readily available, you can create it on a Windows 10 computer or on a Linux or Mac computer.

1] Delete Linux partition from Windows 10

To delete the Linux partition from Windows 10, do the following:

• Log into Windows 10.

Alternatively, you can run the command below in an elevated CMD prompt to set the correct EFI executable as the default boot entry:

To see if the above command worked, reboot your computer. If successful, it should boot directly to Windows.

• At the desktop, press Windows key + R to invoke the Run dialog.
• In the Run dialog box, type diskmgmt.msc , hit Enter to open the Disk Management tool.

Linux partitions are differentiated from Windows because they don’t have a drive number and file system. While, Windows partitions can be identified by the drive label such as C, D, and E. They are also usually FAT or NTFS files.

• To delete the Linux partitions, right-click on each one and choose Delete Volume.
• A warning will pop-up letting you know that you are trying to delete a partition that wasn’t created by Windows. Then, you will be asked if you want to delete it.
• Select Yes.
• Repeat the process to delete other Linux partitions.

Deleting the partitions will free up space on your drive. Now, you’ll need to extend your Windows partition to occupy the free space.

After the process is complete, you will see only one volume meaning you have claimed all your disk space back to Windows.

You can now proceed with the next step.

2] Repair the Master Boot Record (MBR)

Linux has now been removed from your computer, but its boot loader persists. We’ll need to use a Windows installation media to repair and rebuild MBR so as to overwrite the Linux boot loader with the Windows boot loader.

Note: If the bootrec.exe /fixmbr command didn’t work, you can try Automatic Repair from the Advanced troubleshooting options.

Once done, you can now restart your computer. It will boot from its hard drive, starting Windows normally. All traces of Linux should now be erased – but, if when you boot the computer and you’re presented with the dual-boot menu, listing the Linux distro you’ve just removed along with the Windows 10 OS, you can remove the dual-boot menu, so that the PC boots directly into Windows 10 when you restart your computer, by following these steps:

• Press Windows key + R to invoke the Run dialog.
• In the Run dialog box, type msconfig and hit Enter.
• Go to Boot tab.
• Select the Windows 10 entry.
• Click Set as Default button.
• You can delete the Linux entry by selecting it and then clicking the Delete button.
• Click Apply.
• Click OK.
• Restart your computer.

Amazing computer tips and tricks for the technology geek!

There are times when we are using 2 operating systems on a single computer and being a Linux user, you might want to shift to another version of Linux so you might want to delete the other version of Linux from your computer. Here is this post, I will show you how to get rid of the Linux OS from your computer.

The process is very simple. We first need to delete the partition in which Linux is installed, then we need to extend the Windows partition to utilize the free space and finally restore the Windows boot loader in the partition as Linux has it’s own boot loader (GRUB) installed in it otherwise.

Important : Keep a back up of your system as any mistake might cause problems to your computer.

1. Deleting the Linux partition from the disk

Go to search and find diskmgmt.msc and open up the Disk Management tool.

Find you Linux partition (Hint : Locate the partition which has no label under the File System column. Windows partitions will have a label NTFS)

Next, right click on the Linux partition and click on delete volume. This deletes the Linux partition from your computer leaving free space on your hard disk.

(Note : If you see a green box instead of the Linux partition, you will have to delete the volume again so that it shows unallocated space)

2. Extending the Windows partition to occupy the free space

Now chose any Windows volume that you would like to expand, right click on it and select extend volume. Utilize all of the unallocated space by allocating it to the Windows’ volumes.

3. Replacing GRUB with the Windows Boot loader.

Now insert your Windows recovery disk ( or the recovery USB drive ) and boot from it.

Chose the option repair your computer, then select Troubleshoot and lastly select command prompt.

In the command prompt, type in the following command : bootrec.exe /fixmbr

This will replace GRUB with the Windows boot loader. You can now restart your computer which will boot from its hard drive, starting Windows normally.

Uninstall a Linux Dual-Boot System From Your Computer

If you have installed Linux on its own partition in a dual-boot configuration, there’s no easy uninstaller that will remove it for you. You will need to delete its partitions and repair the Windows boot loader on your own.

How you uninstall Linux will depend on how you’ve installed it. If you installed Linux as your only operating system, you’ll have to reinstall Windows over Linux to get your Windows system back.

If You Used Wubi

If you installed Ubuntu or a similar Linux distribution like Linux Mint with Wubi, you’ll have an easy uninstaller. Just boot into Windows, open the Control Panel, and locate Ubuntu in the list of installed programs. Uninstall it like you would any other program and the uninstaller will automatically remove the Ubuntu files and boot loader entry from your computer.

Note that this entry will only be available if you installed Ubuntu inside Windows with Wubi.

If You Installed Linux on Its Own Partition

If you’ve installed Linux on its own partitions in a dual-boot configuration, uninstalling it requires removing the Linux partitions from your computer and then expanding your Windows partitions to use the now-free hard disk space. You will also have to restore the Windows boot loader, as Linux overwrites the Windows boot loader with its own boot loader, known as “GRUB.” After deleting the partitions, the GRUB boot loader won’t boot your computer properly.

Delete Your Linux Partitions

First, you’ll need to delete the Linux partitions. Press the Windows key to open the Start menu or Start screen, type diskmgmt.msc into the Start menu or at the Start screen, and then press Enter to launch the Disk Management application.

Locate the Linux partitions, right-click them, and delete them. You can identify the Linux partitions because they have no label under the “File System” column, while Windows partitions will be identified by their “NTFS” file system.

Be careful while deleting partitions here – you wouldn’t want to accidentally delete a partition with important files on it.

Next, locate the Windows partition near the newly available free space, right-click it, and select Extend Volume. Extend the partition so that it takes up all of the available free space. Any free space on your hard drive will remain unusable until you assign it to a partition.

You can also choose to create a new, separate partition instead of expanding your current Windows partition, if you like.

Fix the Windows Boot Loader

Linux has now been removed from your computer, but its boot loader persists. We’ll need to use a Windows installer disc to overwrite the Linux boot loader with the Windows boot loader.

If you don’t have a Windows installer disc lying around, you can create a Windows repair disc and use that instead. Follow our instructions to create a system repair disc in Windows 8 orcreate one in Windows 7.

Insert the Windows installer or recovery disc into your computer and restart your computer. You’ll need to access the Command Prompt from the disc. The instructions and screenshots here are for Windows 8, but you can follow these instructions to access the recovery Command Prompt with a Windows 7 disc.

Click the Repair your computer option after booting from the disc.

On the Choose an option screen, click the Troubleshoot icon.

Click the Advanced options tile, and then click the Command Prompt tile.

Once a Command Prompt window is open, type the following command and press Enter to run it:

You can now restart your computer. It will boot from its hard drive, starting Windows normally. All traces of Linux should now be erased.

After installing Windows 10 on a partition, I want to remove Ubuntu 18.04 completely and use the entire hdd for Windows. Can I delete the partition with Windows still working? I’m not sure if grub will affect the boot.

3 Answers 3

Follow the below steps properly:

STEP – I: Deleting Ubuntu Partitions

Boot into Windows OS

Press Windows + r keys together and type diskmgmt.msc to enter into your disk management utility

You can easily recognize the Ubuntu partition by their size. Another hint to recognize the partitions is to look at the partitions which don’t have a file system and drive number. Windows partition is labeled with a drive number such as C, D, E etc and are usually in NTFS or FAT file system

Manually select all your Ubuntu partitions one by one and right click on each and select the option – Delete Volume

All the deleted space will show as Unallocated on your Windows partition table. Now, either extend any of your existing partitions or simply create a new partition (using the entire Unallocated space you got)

STEP II: Fixing the Boot loader

Use your Windows OS disk and restart your computer. Press F10 or F12 at the boot time to go into BIOS/UEFI and choose to boot from removable disk

Select ‘Repair your computer’ option

Go for the ‘Troubleshoot’ option here and then select ‘Advanced options’

Look for the ‘command prompt’ option and select it

Once you enter into the command-line interface, type the following command: bootrec.exe /fixmbr

Once it’s done, restart your computer and this time boot normally from the hard disk. You should be able to boot into Windows.

In case you encounter Grub rescue error, try the steps below:

If the command bootrec.exe /fixmbr did not work, try the ‘Automatic Repair’ option in advanced troubleshoot option

It will find the issue and take some time to repair it

Once done, reboot your system and you should be able to boot into Windows OS directly (with no GRUB options).

We have been getting questions from users about how to delete a linux OS from their hard drive. Well, lets oblige them. Uninstalling an OS is not like uninstalling a program with the simple “click to uninstall”. It’s a little trickier than that, however not that difficult. I will show a comprehensive method of removing a Linux OS, which is the correct term than uninstalling. These procedures will work on dual boot or single OS systems.

First you can not delete any partition on a drive if it is mounted. You will have to unmount the drive first to proceed. To umount a drive that has the linuxOS on it:

1. insert a liveCD, and boot to the desktop. I recommend using the live ubuntu CD

You are now using your system via the liveCD, no drive on your system is mounted. From the live desktop, you have two options to delete the partition. You can either use a gui tool like gparted, which is located in systems>administration or fdisk from the command line. From the gparted window, there is a drop-down menu arrow that allows you to select any drive that is located on the system.

In you the drop-down menu, select your require drive. You will get a listing of all the partitions on your hard drive. Select the required partition, and in the action menu, select delete. Then select aply changes. That’s all it is too it. This works if you have only one OS on the hard drive.

Another method, which I like, is to use the fdisk command. To access the fdisk command:

1. open a terminal
2. type fdisk /dev/

The fdisk program has a lot of advanced features that come in handy when you need to make special changes to your hard drive. When you type the fdisk command you must specify the drive you want it to access. The drive specified by the drive files located in the folder /dev/. If your drive is a sata drive, you will specify /dev/sdax, or if it is an ide drive, you specify it with /dev/hdax. The variable x represents ths partition number.

Once you are in fdisk, you are given the option to list all the commands used with fdisk which is accessed by pressing the m key. Press the p key, and you will get the information pertaining to your hard drive.

Reading the information from your hard drive, you will notice a partition table. If you have only linux installed, you will see two partitions, a swap partition and an ext partition. If you have two OSs, windows and linux, you will in addition see an ntfs partition. Each partition will have a number after the sdax syntax telling you what number partition it is.What you are going to do is delete the ext partition by pressing the d key and selecting the partition’s number. The fdisk program will help in the operations, all you have to do is follow what is says.

Keep in mind, nothing is changed unless you press the w key that force fdisk to write the changes to the drive. This is very useful if you accidentally select the wrong changes.

Notice, while reading the partition table, their is a boot column. The row of the ext partition has a “*” under the boot column heading. This means that this partition is the partition your system will boot from. You want to move the “*” to the ntfs partition, so your system will boot from that partition. You first remove the “*” from the ext partition by pressing the a key and select the partition number that you want to remove the “*” from. Then you must add the boot flag “*” to the ntfs partition. Press the a key and select the ntfs partition. Confirm you have made the right changes by pressing the p key to view the partition table. Once confirmed, press the w key to apply the changes.

Remove the liveCD once you reboot the system. You should see your windows OS loading, or start a fresh OS installation. Happy operating.

OK, so, you’ve tried a Linux distro for netbooks (like Ubuntu) and you’ve decided, “Hey, I don’t like this.” I’ve been there, too.

But now, whenever you boot, you get an annoying GRUB menu asking you to select what OS you want to boot into, and you have to scramble to switch to Windows 7. Plus, you’ve got a swath of disk space you can’t use anymore because the Linux distro you don’t want any more is using it. Most people would advise using a Windows repair disk, which isn’t really helpful on a netbook. (But if your netbook runs Windows XP, you’re going to have to make a Windows XP USB boot disk or boot from your vendor’s recovery partition either from the BIOS menu or from an entry in GRUB; the manufacturer’s manual will tell you how to do that).

The good news is if you run Windows Vista (unlikely, as it wasn’t shipped with many netbooks) or Windows 7 (much more likely), you can uninstall Linux from your netbook without a repair CD. To do so, boot your netbook and select the Windows 7/Vista entry. As soon as you do this, start hitting the F8 key until you reach a startup options menu. From that menu, choose “Startup Repair” (normally the first option). Windows setup will then load, ask you to select your language, and, if you have a password-protected account, ask you to log in with that account. From there, select “Command Prompt” and in the prompt run the following:

The system should respond with “The operation completed successfully.” Close the command prompt and choose the “Restart” button to continue. At this point, your netbook should boot directly into Windows 7 without GRUB appearing at all. Once Windows has started, right click Computer in the Start menu and choose “Manage.” You’ll need to “Allow” this if UAC is enabled. From the left side of the window that appears, choose “Disk Management” under “Storage.”

At this point, you should see all of your drives listed, as well as the one or two primary partitions, without any label or file system information. You can now delete these to recover the hard-drive space from your Linux installation. DON’T delete any entry marked “recovery partition,” however; these are restore tools provide by your vendor to allow you to reinstall Windows if necessary — you want them around. Once you’ve deleted the Linux partitions, you’ll see a healthy chunk of free space on your drive. You can select the NTFS partition nearest this block from the free space, right click it, and choose “Extend volume” to add this free space to your volume.

That’s it! Linux is now totally removed from your netbook.

Addition 1: Windows won’t let me use “Extend volume” after deleting Linux

This can occur in a number of situations, including having the free space to the left of the partition to extend or if Windows has decided to store system files at the end of the partition. If this happens, you have two choices.

Your first choice is to make a new drive in the empty space and assign it a new drive letter. This will make the additional space appear as a second drive in “Computer,” and you can use it that way (although it won’t give you additional space in your primary partition).

If your heart is set on expanding your primary partition, your best bet is to use GParted, humorously enough, from whatever USB drive you used to installed Linux in the first place. Use the “Try” or “LiveCD” option of the distro, open a terminal, and run “sudo gparted.”

Select your main drive from the top-right drop-down menu. This will let you expand the main partition as you see fit. (Don’t delete any partitions from here). Once you’re done, you can save the changes to the drive and restart. Chkdsk will probably run the first time Windows starts; this is normal and doesn’t mean anything is wrong with your drive.

Did you mess around with Ubuntu while dual booting? Do you too want to remove it completely now? Then take a sip. The post is for you.

So let’s start. Run windows and open disk management. (You can search it or click on the option directly on “start” menu)

Once the disk management window opens, identify the Linux(Ubuntu) partitions and remove it. To do so, follow the process. Check the partitions which has no drive names and are larger than 1gb. (Hint: choose Healthy primary partitions) Once you have identified the partitions, right click >> Delete volume >> Yes.

If you have free space (unallocated memory), merge it with another partition to use it back again later. To do so, right click >> Extend volume >> Next >> Next >> Finish.

Ah, Kudos! You did it :))

Reboot the system.
You will still find ubuntu on the boot menu. This is because you have just deleted the Linux partitions whereas the grub boot loader is still present in your PC’s efi partition. So the next step is to remove it.

For this, first launch command prompt as administrator. (Start>>CMD>> run as administrator). Now type “diskpart” to start the diskpart utility. Now type “list disk” to identify the efi partitions. Now type “select disk 0”. Then type “list partition” and identify the efi “system” partition. Then type “select partition 2”. In my case, the efi partition system had partition number 2 and it might vary in your case. Then type “assign letter=x” (I chosed x and it’s random). Now you will see a 100 mb partition in windows explorer. That’s your efi system partition. This is for our knowledge. We don’t need to do anything here. Let’s get back to our command prompt. Now type “exit” to close diskpart. Now type the letter which you have assigned in the CMD line and place a colon with it. I am typing ” x:” and pressing enter key. Now type “dir” to see the contents of drive x. Now we have to change folder so type “cd efi” and type “dir” to see the contents of efi folder.

Now you will be seeing the list where a folder named of Linux that you have installed once (like Ubuntu, fedora, blah blah). That’s the folder which we want to delete. Type “rd /s”. I am typing “rd ubuntu /s”. Type Y to conform deletion. Type “dir” to ensure the folder is deleted.

Yes, we did it.
Now we have successfully uninstalled Ubuntu completely from our PC. The efi system which we mounted will automatically get unmounted once you restart your PC. Don’t worry.