Question Crashing to a black screen with cursor

Mar 16, 2019
I'll start from the beginning:

The computer has been working flawlessly for about two years. No problems at all. I've gone through the stickied checklist, and with the exception of breadboarding my mobo I've taken all the steps I can.
  • Computer suddenly powers off, and will not power on at all. I figure the power supply has failed, as they do, and so replace it. Re-plug all the plugs, reset the CMOS and boot into the BIOS to do a fresh install of windows.
  • Install Windows 10 successfully. Boots into desktop, and I start the updates.
  • Computer crashes to a black screen with cursor. Cant Ctrl+alt+Del, cant do anything except a hard reset.
  • Try a new fresh install, same thing happens. I figure my SSD must have gotten corrupted or gone bad when the power went down.
  • Replace the SSD and do a fresh install of Windows 10. Same thing happens: Windows finishes installing and then I reach the desktop, after a couple of minutes the computer crashes to the same black screen with cursor and I cant do a thing.
  • Hard reset 3 times in a row in order to get to safe mode (Thanks Microsoft for getting rid of the F8 option)
  • Go through all the repair options available. Windows can't figure out what's wrong.
  • Go into Command Prompt and run chkdsk: after three hours of checking, everything comes back normal.
  • Booted into Memtest86 and everything came back green. No errors, no faults, everything is good.
  • re-checked all the wiring: no bent/broken pins, everything is well seated, nothing shorting out.
So now I'm not sure what the next step I should take is. Based on the steps I've taken is it conclusively my motherboard that's busted?

Thanks for your help and advice!