/edit/ okay I reread your post... do you have both onboad vid and the pci card enabled... if yes all you have to do is check a box somwhere under display properties and you should be ready to do... if you disabled the onboard video, you'll just have to enable it and load the drivers.../edit/
I guess you'll just have to get a pci card... just make sure its not too old... multiple vid card under 98 didn't work for me when i tried to use a 6yr old cirrus logic vid card... works fine with most newer vid cards though...