Building a new system with 8600GTS, Intel 6750, mfg spec Kingston DDR2. Using Asus PN532-E SLI Plus MPCB. First one worked 40 minutes, was using Corsair 520W PS, thought the PS got a little hot, 2nd Mobo worked ~10hrs using Ultra 800W PS, the PS never even got warm. I don’t think PS was a problem though. In both cases the PC just shut off while running. First time while loading OS, 2nd time I think I was transferring files or something mundane. When you hit the on/off switch the fan starts to spin as to power up for not even 1/10th of a second and then stops. Something is telling the PS to not apply power, kind of like when you to a shut down and ground is no longer applied to the PS_ON pin of the PS. It is strange 2 boards went out like that. Any suggestions? As I wait for 3rd PCB, I wonder if anything might be causing the problem. All parts are new. Could it be a bad video card, but it did work on 2nd new PCB for the 10 hours. I wonder if ASUS has a bad lot of mobos. Any thought appreciated.