Question BSOD after changing BIOS from UEFI to Legacy ?

Amaggard

Distinguished
Oct 12, 2015
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I used a partition manager to change my BIOS from Legacy to UEFI (MBR to GPT) because I heard it is faster and I need it to be on UEFI to upgrade to Windows 11 if I wanted to, but it was causing issues with shutting down and sleep mode. I changed it back from UEFI to Legacy (GPT to MBR) with the same partition manager but didn't know that I can't just convert it back like how I did it. After restarting, it gave me a BSOD that says "Your PC needs to be repaired." and gave me the error code 0xc000000e, and says that my system couldn't be loaded because the file "\windows\system32\winload.efi" is missing.
It gives me 3 options:

Press Enter to try again
Press F8 for Startup Settings
Press ESC for UEFI Firmware Settings

I pressed ESC to get to my BIOS settings, and I was hoping that changing it from "UEFI" to "LEGACY+UEFI" would work, as that is what it was on before I changed it to UEFI, but that made it much worse because now I can not enter the BIOS at all. When I turn on my PC now, what happens is I can't even enter BIOS anymore, and no matter if I press "Enter", "F8", or "ESC", nothing happens.

Afterwords, I found out about putting Windows Installation Media on a USB and booting to the USB to run the setup and repair/reinstall windows, but unfortunately since I can not go into my BIOS anymore I can't boot to the USB. I was hoping it would automatically boot to the USB before the blue screen but I have had no luck with that either.

Where I am at right now is I am planning on taking out my C drive, the drive with the OS on it, and plugging it into my friend's motherboard and using a partition manager to change it back to UEFI then plugging it back into my computer and hoping it will work. I want to know what anybody else thinks I should do, or if I am going to make it even worse by doing that.

If all else fails, I can just wipe the drive and reinstall windows on it from scratch since a majority of my files are on my other drives, but I would like to avoid that if I can.
 

Lutfij

Titan
Moderator
I used a partition manager to change my BIOS from Legacy to UEFI (MBR to GPT)
You should've just backed up all your mission critical info and then reinstalled the OS after setting the BIOS to UEFI.

If you're on a PC, you can clear the CMOS and that should prompt you to see the BIOS splash screen once POST process is over.