I have failed to diagnose and fix the problem PC. I have placed three different drives in the system and eventually I got the no boot scenario/BSOD on all of them with error code 0xC0000001, or 0xC0000225. None of the boot repair options worked so maybe the drives have been damaged by the PC even though the board voltages appear OK. The built-in PC diagnostics say it is unable to find the High Precision Timer and then promptly freezes. It just isn't worth spending more time on this even if I found the issue. I rode that dinosaur for all it was worth.