computer starts, no display. (video card is fine)

I have a P3 550mhz, 192mb ram, gigabyte motherboard, etc.

When I turn the computer on, it comes on but the display does not.

The video card and monitor are fine (ive checked them on another computer) and there is nothing visibly wrong with the motherboard or anything.

Any ideas?

Thanks, Ian

Make sure the video card is fully seated.