I upgraded from Windows 7 to Windows 10 and it was working fine for a few days but now whenever I try to boot it up I get BSOD with error code 0xc000021a.

I've tried the following 'fixes':

System restore --- Runs for a few minutes and then says "Could not restore your computer. No changes were made"

Clicking on any of the advanced startup options --- BSOD

Reinstalling windows 10 with a usb --- Results in it going into circles with this messagea "The computer started using the Windows installation media. Remove the installation medial and restart your computer so that Windows starts normally. Then, insert the installation media and restart the upgrade. [Do not select iCustom [advanced]I to perform an upgrade. iCustom [advanced]I installs a new copy of Windows and deletes your programs and settings.)"

I've taken the usb out and restarted the computer several times, even called Microsoft Technical Support. They had no idea what to do.

I used to be able to access the command prompt and I tried everything suggested in this article here 0xC000021A Fix for Windows XP, Vista, 7, 8, 8.1. The reason I say "used to" is because things recently got alot worse when I changed the boot order and now it just turns black after the bios screen. I've tried to restore the BIOS setup to default settings and I also tried everything suggested in this article 3 Ways to Reset Your BIOS - wikiHow but nothing works.

To recap, it all started 2 days after I installed windows 10. Everytime I tried to boot I got BSOD with error code 0xc000021a. I tried everything and nothing worked. Then I changed the boot order in BIOS setup and now it just turns pitch black after the BIOS screen, so I can't really do anything anymore.

I've called microsoft support and spammed forums for 4 days now and no one has been able to help me.