Hello. I am having troubles with my Geforce 8600 GTS graphics card. It was installed and working fine when my computer was running vista. After i installed windows 7 it appears the graphics card has stopped working. The graphics card doesn't appear in the device manager, and my monitor doesn't display anything when i plug it into the graphics card. When i tried to install the drivers it said nividea could not detect appropriate hardware. I just tried unpluging and plugging it back in that didn't do anything. The graphics cards fan spins when i turn it on. Also i tried looking around in the BIOS but couldn't find anything useful.
I also want to say there was a bit of time before i installed windows 7 and realized the graphics card wasn't working
it seems to me your cards might at it's end or your mobo pci-e slot going bad. if re-seating the card does not help the fastest way to know if your card are still working properly are using different pc to test it out. it could be psu problem as well but we dont want changing stuff before we know what are the real cause of the problem