I have an Emachine desktop running XP that worked fine until one day the screen went black while the pc was still running. I needed to do a hard reset to shut it off. The problem got worse and worse (good thing I had an external HD that I was able to back up most of my files to), where the problem happened anywhere from 5-15 minutes after startup to not starting at all. I've tried booting in safe mode, but that doesn't work either. I've since bought a new pc, but I'd like to know what's up with the old one before I junk it or decide to fix it and sell it/give it away.

Thanks!