I have very strange problem. i bought amd 6850 graphic card and i have strange problem with it. at the beggining ti worked gr8, with one issue. before every boot I have to unplug my pcu from the powergrid for around 15- 20 sec and then plug it back and computer boots normally, if i dont unplug psu computer starts, and sounds normal, but the ventilators on my gf are spinning on full speed and i don't have any picture on my monitor. then i have to turn my comp off, unplug it for 20 sec and then it boots up normally. after it boots i dont have any problems with it, runs gr8, video is fantastic and no bugs while playing games. I've run every test I could think of and everything was ok, once it boots up it works fine.
that was untill this morning, summer is coming and it was time to clean all the dust from inside the case to increase the airflow, i took my computer apart, cleaned it and put it back together and tryd to turn it on, everything is as it use to be, but now i dont have any picture even if I unplug psu from the grid. there aren't any error beeps from the motherboard, no strange sounds from the inside of the comp, it sounds like normal boot up. i checked everything, and everything is plugged in, i tryed to boot with my old graphic card and it works fine, i tried 6850 in my girlfriend's comp and it works gr8 there... i just can't make any sense of it
I have phenom 2 x4 965
8 gigs of ddr
chieftec A-80 Series 600w psu
Sounds like a bad PSU. Does your girlfriend have the same power supply in her computer? Go to www.hardwaresecrets.com and look in the power section, it will give you a good idea of who makes a good PSU and who does not. I myself run Corsair or Seasonic, maybe an Antec on lower budget systems.