I have this old Optiplex 760 that I had upgraded with a Core 2 Quad Q8600 and 8GB of RAM for quite a while it’s been running fine if not slow but recently it stopped displaying video. At first I though the graphics card had finally died but when I replaced it with a working one it still did t display. Integrated works fine but can’t run anything since it’s Intel 4 series graphics. The computer completely acknowledges the graphics card and will complain if I plug a cable into the integrated port while it has a graphics card in the pci slot. I don’t know what the original card I had in it is but the new one was a HD 7570. The only error I get is just that the cmos is low. I don’t have one to replace it with though and it shouldn’t make a difference.