I am having the same problem. 2 X EVGA GTX260 were working fine till last night. Power this morning, and one card disappeared. The 3 monitors power up, but then it says no signal. so now only card is seen in device manager. Also, the resolution went down. 2 of the 3 monitors are in stanby, so I am pretty sure the graphic card is fine. PSU is 1000 watt , new PC HPVoodooDNA. I think it's something with windows 7.