Bootloader issue - How do I completely remove Linux from my system? fully detailed description

Question

The goal was to successfully install Windows 10 upgrade.

System configuration : Dell Inspiron 3537, i5 4th gen processor, 6GB RAM, 1TB HDD, 2GB AMD Graphics.

Before install : I have a Dual-boot system with Ubuntu GNOME alongside my genuine Windows 8.1.

I assumed there would be a problem with the bootmanager so I decided to remove the Linux from my system. Followed the instructions given in the how-to-geek website tutorial(linked at the end).

Accordingly,I deleted 2 partitions 65GB and 2GB(I guess swap partion). Screenshot added to the gdrive folder

Next,I booted into Windows Repair from Disc and entered in cmd:

bootrec.exe /fixmbr

After removal the problem began,(gdrive link with screenshots given at the end)

The first boot screen:

GNU GRUB version 2.02~beta2-9ubuntu1.2

    Minimal Bash-like line editing is supported. For the first word,TAB lists possible command completions. Anywhere else TAB lists possible device or file completions.
    grub>exit
    Boot succeeded-info

The second boot screen:

Boot Manager (windows)

The third boot screen:

Windows 8.1/10 boot up (Dell logo)

Then the system finally starts Windows.

I installed Windows 10 upgrade,still the same problem.

Please guide me through removing Linux entirely (removing grub) from the system. I want to clean-install Windows 10 of which I know the process how-to-do-it.

Do I remove the EFI partition too?

Do I just directly perform a clean install?

Please help. Thanks a lot!

Links:

Gdrive screenshots: https://goo.gl/hUZIKG

How-to-geek tutorial: http://goo.gl/Wqk4pe

Answer 1

First, you wrote:

I do not have enough portable storage for backup

FIX THIS PROBLEM IMMEDIATELY!!!!!

I frequently see problems on this and other sites caused by people who have inadequate backups. Because of accidents or hardware failures, they lose all their personal data.

That out of the way, your computer uses EFI firmware, not BIOS. One of your repair attempts used bootrec.exe /fixmbr, but that works only on BIOS-based computers. Under EFI, the boot process involves:

1. An entry in NVRAM tells the computer what boot loader (stored on the EFI System Partition, or ESP) to launch. In fact, a list of boot options is stored; each one is tried in turn until one succeeds.
2. Control passes to the boot loader specified by the NVRAM. This boot loader may do any number of things, but ultimately....
3. The boot loader loads an OS kernel.

Your problem is caused by the fact that GRUB 2 (the usual Linux boot loader) is often configured to rely on files stored on the Linux filesystem. Thus, when you deleted the Linux partition, the EFI continued to launch GRUB 2 (which was stored on the ESP), but GRUB 2 was unable to read its configuration file, and you got the emergency grub> prompt. This is a design flaw in GRUB 2, or at least in the way it's often configured -- it really should not be depending upon configuration files stored anywhere but on the ESP.

There are two solutions to this problem:

1. Delete GRUB -- If you delete the GRUB files from the ESP, the firmware will move on to the next item in the boot list. To do this, you must mount the ESP in an OS (or launch an EFI shell) and delete the files, which are normally stored in a directory like EFI/ubuntu or EFI/fedora (depending on the distribution you installed). The ESP is easy to spot with most partitioning tools, since it's a FAT partition early on the disk. Sometimes it's marked as an "EFI System Partition" or something similar. Your first screen shot shows it, in fact -- it's your second partition. In Windows, you can mount it with the /S option to mountvol, as in mountvol /S E: to mount it as E:. In Linux, it mounts like any other partition, with the mount command.
2. Re-organize your boot order -- This can be done with efibootmgr in Linux or bcdedit in Windows; however, in Windows the EasyUEFI utility presents an easier and more flexible GUI way to control the boot order. Whatever tool you use, delete GRUB 2 from the boot order, or at least move it below the Windows boot loader in priority. To use efibootmgr, first type it alone to see what boot options exist; then use -b and -B to delete one, as in efibootmgr -b 5 -B to delete the Boot0005 entry; or use -o to rearrange the boot order, as in efibootmgr -o 2,5,3 to have the system try Boot0002 first, then Boot0005, then Boot0003.