Well, if he receives the stop error before he can get into safe mode, he has a piece of faulty hardware, because the operating system hasn't even made it past the bootloader yet. If the stop error happens after the Windows splash screen, it is a driver issue, and can be corrected without, in most cases, resorting to a repair install.
By the way, when was it posted that he can't get into safe mode?
Let think about it:
Faulty RAM? Hmmm....possible, but it would have come up with CMOS error. Bad RAM black screen... Beep.. beeep ..beep
Bad HD? I could go with that, bad sectors happen to the best of us. However Windows should have picked that up during the install/repair
Well, I'll check back in later. Hopefully he can give us more details, so we can figure this out.
I'll be back later on. Hopefully he will give us more info
If Hardware wise... I'd put money on the MB... unless CPU overheated. (it should have went into a thermal shutdown)