Trying to get S2518 working with add-on PCI video card

Ive got an S2518, dual 1.4ghz pentium 3s, 2gb ram, 3ware 9500S-8 with 1 80gb sata hard drive and ive got 1 IDE 160gb hard drive as my boot drive, using windows XP

It all works great except I bought a PCI video card for the system, a nvidia 9500GT. The card will not detect under windows XP no matter what I try it seems. I updated the motherboards BIOS and its now the newest, but still nothing. When I plug the monitor into the add-on graphics card, windows still reports the only display adapter as the onboard ATI Rage? But everything still shows up, kind of weird I think since its plugged into the 9500gt.

I tried using it in both PCI-X slots, tried 66mhz and 33mhz PCI, tried looking through the BIOS, cant seem to find anything to disable onbaord graphics

Video card is verified good, as I put in into another PC and the card works great, tried it in games and everything.

The motherboard manual is no help, mentions nothing about installing an add-on graphics card or disabling the onboard graphics.

Any help would be greattt

Thanks, Tim