I have a ASUS P4V8X-MX motherboard which has onboard video and a AGP Slot. Problem is that if I try plugging in a AGP video card and power up, the system just beeps and the screen stays blank (regardless of where the monitor is plugged). There's no option in the BIOS nor is there a jumper to set to disable the onboard video, so I assume this motherboard is supposed to automatically disable the onboard video if a AGP card is plugged in. Apparently that function is not working, so for now I have to use the onboard video just to use the system. Btw the video card I'm trying to use is the Inno3D GeForce FX5200.

Any idea why this is happening? I once used another PC (a Compaq Presario) that had a similar setup but had no qualms about plugging in a AGP video card (it automatically disabled the onboard video).

is the card plugged into the power supply?

Go into bios > advanced > chipset

Change "Primary Graphics Adapter" from PCI to AGP.

M3th:

This particular graphics card does not have an external power connector, so it definitely draws power from the AGP slot itself. (And just so you know, the graphics card is definitely functional because I previously used it on a ASUS P4PE-XT/E motherboard without problems.)

American Zombie:

That BIOS setting is already configured to "AGP".