could be alot of stuff.....but you said, originally, that you shut this system down because of high cpu temp. Is it an intel or amd cpu and what type. 60 degrees c may not be all that high for a scoket a amd cpu if that's what you have. The cpu could have heated up if the psu voltage was taking a dumb. switch out power supplies on the system and wee what happens. It's an amd64 what?
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EVGA 680i, Dual EVGA 8800GT'S (650/950), 4 gigs OCZ DDR2 1066, Intel Q9450 at 3.8 Ghz, Koolance Water Cooled, Dual Plextor16x DL DVD+/-RW. Dual WD 250gb 16mb Cache Sata 3.0. 3DMark06 score = 19,168.