Hello everyone, I recently came across a really unusual problem and exhausted all possible solutions. The system is an HP desktop Pavilion model m8400f. This model came with a Nvidia GeForce 8500 GT. One day the PC stopped sending it's video signal through the video card's DVI port, and was using the onboard graphic's VGA port instead. I figured the video card might be dead, but I checked and the video card's fan was still running. I took it off and performed maintenance on it; cleared the heatsink of dust, reapplied thermal paste, etc. I figured maybe it was a fluke fail, so I carefully reseated it into the PCI slot and rebooted. No luck, still refused to work. I went out and got another card, an Nvidia GeForce 210. I installed it onto the motherboard, installed necessary software/drivers, and it works great. Doubting that the old card is dead without any trace of damage, I put it in another PC of mines and hoped it might still work. To my surprised the card was working fine, and after installing drivers the entire card was in working order (HDMI, S-Video, and DVI). I then tried putting the old card back into the computer/motherboard in question. Still no luck. I fiddled with the BIOS settings, and got nothing out of the video card's DVI/HDMI ports. The OS detects no change in hardware (other than the fact that I took the new card out and the motherboard is now using onboard graphics). Other things I've tried include: - Reinstalling drivers. - Updating BIOS. - Checked BIOS settings. - Checked hardware. (no damage what so ever) To state again, this is an old OEM motherboard that refuses to detect the OEM video card that it came with. I'm at a loss now, just what is the problem?