I have just finished the build of my new rig and the last thing I had to do was install my 580. I cannot get a video signal on it and doesn't seem to work. The fan is spinning at a normal speed and it certainly isnt underpowered. It isn't the mobo as I can run and post my 8800gt with no issues at all.
Asus P67 Sabertooth
Corsair Vengance 8GB
1TB WD Green HDD
BeQuiet! 730w PurePower Modular PSU
Not sure where to go with it.
Tried second PCIe slot
Tried a spare PCIe Power Lead
Tried using the 6pin Molex power lead
Try a different port. My hd6850 will only use one of my DVI ports, the other doesn't work, but it fits. They are different styles of DVI. It could be the same problem where your DVI is fitting, but not getting a signal.
Hm. Make sure the connection to the monitor is nice and tight too. Also, some monitors are set to different ports. My friends has a button that switches from VGA, DVI, and HDMI. If you are on HDMI or VGA (Assuming you use DVI), it won't get a signal.
Haven't had chance to even set the res on the 580 as it's black screen at post. doesn't show a thing. tested the 8800gt on same rig and it works so it is the card. Just got the ok from amazon to return it and have a new one sent out