When I start up this computer it starts the self test (I see the lights on the disc drives come on) then it shuts down and starts all over again. I have been told that this is a possible power supply issue (underpowered) or maybe a mobo fail. Did not do this until I installed a BFG Nvidia 260. When I first installed the card it did this but then seemed to "clear up" from the problem after a couple of "recovered from a serious error" msgs and ran fine for a day. This is a friends computer but I built it 2 years ago and virtually no problems til now. Computer was extremely dirty with nicotine laden dirt and dust clogging fans and entire insides when I got it to put in the card which i cleaned all out and got it looking like new again. Has a 650W power supply in an Antec 900 case, 5 fans, 2 disc drives, 2G Ram, MSI P5N mobo, Intel core 2 Duo. Any opinions or ideas??