i have gigabyte motherboard GA-78LMT-USB3 (rev. 6.0) . My video card on pci express slot was working fine. it doesn't work anymore i think . i tried my working spare video card too but still doesn't work. only onboard video works. I'm stuck. can someone help me with this issue? thank you. I've also updated my bios and tried to disable the onboard video and still don't work the pci express slot. It worked before but sometimes worked and sometimes didn't work. this is hard to figure out, as I tried many options for troubelshooting my video problem. help!