Windows 10 Won't Boot UP: Just Loads A Black Grub Screen with a >

My Windows 10 won't boot up anymore. When I try to boot up, I just get a black screen with:

grub >

displayed on it.

Above that, it says:

Code:

Minimal BASH-like editing is supported. for the first word, 
TAB lists possible commands completions.Anywhere else TAB lists 
possible device or file completion 
grub>

The Computer is an HP Compaq Elite 8300 SFF

Here's what happened (if you need the backstory):

Windows 10 was working fine before. I wanted to convert this computer to running Linux (Mint 19).

I pulled out the hard drive with Windows 10 on it, and put in a DIFFERENT hard drive and installed Linux Mint on to that hard drive. It works fine, by the way.

I wanted to boot into windows 10 again, so I swapped hard drives and tried to boot. That is how I got this error.

After it wouldn't boot up, I went into the Boot Device Menu. Under UEFI, it lists Ubuntu (same thing as linux mint). Previously it listed Windows Boot Manager.

Under legacy boot sources, it lists SATA0, which should be the hard drive. However, if I select SATA0 under legacy boot sources, I get this error message:

Code:

GPT-Formatted disk.
Legacy boot not supported. Press any key to reboot.

If I have the windows hard drive in the machine but boot up off of a Linux live USB, I can see the partions of the disk with Windows 10 on it look like this:

/dev/sda1/ EFI System Partition fat32 100MiB (size) 53.31MiB (used) boot, esp (flags)

dev/sda2 ! (exclamation point) Microsoft Reserved Partition Unknown (file system) 128 MiB (size) -- -- msftres (flags)

dev/sda3 Basic Data Partition NTFS (file system) 464.53GiB (size) 67.45 (used) 397.08GiB (unused) msftdata (flags)

/dev/sda4 NTFS (file system) 450MiB (size) 383.64MiB (used) 66.36MiB (unused) hidden, diag (flags)

Unallocated unallocated (file system) 583.02MiB (size)

If its uefithen it cant be set to legacy as there is no MBR as such it must be set to boot uefi

planet99 said:

My Windows 10 won't boot up anymore. When I try to boot up, I just get a black screen with:

Code:

Minimal BASH-like editing is supported. for the first word, 
TAB lists possible commands completions.Anywhere else TAB lists 
possible device or file completion 
grub>

This is exactly what I would expect to see if I had tried to install any Linux on the drive. AFIK, Grub is never stored in the Bios. It's also strange to see Ubuntu mentioned in the boot loader. Does restarting a couple of times clear the Ubuntu listing?

After it wouldn't boot up, I went into the Boot Device Menu. Under UEFI, it lists Ubuntu (same thing as linux mint).

That is still consistent with an attempted Linux install. You may have to rebuild the UEFI boot commands.

Garyw said:

This is exactly what I would expect to see if I had tried to install any Linux on the drive. AFIK, Grub is never stored in the Bios. It's also strange to see Ubuntu mentioned in the boot loader. Does restarting a couple of times clear the Ubuntu listing?

That is still consistent with an attempted Linux install. You may have to rebuild the UEFI boot commands.

Thanks for the reply How do I rebuild the UEFI boot commands that you mentioned.

And just to clarify, the linux installation was on a different hard drive that I swapped in. Not this same hard drive, although I don't know if that makes a difference or not.

Samuria said:

If its uefithen it cant be set to legacy as there is no MBR as such it must be set to boot uefi

Thank you for the reply. Can you explain to me HOW to set it to boot UEFI?

Caledon Ken said:

If your BIOS has Fast Boot or some other similarly named functioned please disable and try again.

Yes, I have tried disabling fast boot, and that has not helped. Same thing happens.

By the way: I don't have the original Win 10 install disks. I bought the computer with win 7 preinstalled and then upgraded to win 10 when it was the last day to upgrade for free.

I do have A DIFFERENT computer that has Win 10 running fine on it though if there is something I need to create from a windows machine.

Not knowing the bios its hard to say what setting what do you have in the legecy settings or same menu. Is secure boot set if linux has been added that could be why its showing

Samuria said:

Not knowing the bios its hard to say what setting what do you have in the legecy settings or same menu. Is secure boot set if linux has been added that could be why its showing

Legacy Support = Enabled
Secure Boot = Disabled
Fast Boot = Disabled