I had a similar problem with my AMD machine, turned out I had a defective motherboard...then the replacement was defective, and now I'm on number 3 and its still sort of funky but functional. It also blew a PSU which then burned out a hard drive. Check all the capacitors on the mobo and see if the tops are bulging or broken.

__________________
TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth