If your budget allows, buy a new computer with XP as the OS. The 9600 series is an old generation video card, and you really need to get your RAM to 2 GIGS. If your budget doesn't allow, then upgrade your video card to the fastest card your system can handle and get your RAM to 2 GIGS.
By the way, I wouldn't touch Vista with a very long pole. It's going to need a service pack to make it half decent, and even then I'm not convinced.