I had these issues with my ATI Radeon HD4870 XFX since a long time. Now I can't use it anymore. I lost my old fan so my warranty can't be apply...
My computer can't reconize my videocard. I have the signal from the screen to the computer, but I have that black screen when I boot. I had red dots when I was playing or watching videos, suddently the videocard shut down from the computer, black screen while the computer continue to run. It's like if it was missing power at some point...
I changed the fan, for a bigger one, temp is good. Even at "cold" I have issues.
I have a Antec PSU 500W, Asus P5QLVM-DO, 4 gig ram (no fault during a the test) Fresh installation of Win 7.
I'm now running on the onboard videocard, since that day I have no problem at all.
Is it possible to change or add up voltage in the bios in some way ?
My PSU is working FINE since day one.