you should open up the case and check for a AGP slot ... if there isnt one then the best bet would be a total upgrade .
compac's of your vintage are pritty basic and low end .
if it has a agp slot then id recommend a cheap power colour 9550 256mb video card and another 256 or more in ram . that would get ya gaming .
I may have a spare stick of 256 ddr 3200 laying around . no spare video cards though .