I have a W200 in a Compaq Evo of similar age. It's been discussed here before, but it looks like maybe old messages have been purged from the forum or something, because I can't find it now. No matter though..
Short answer: It can't be done.
Slightly longer answer: It can be done, but it's a real pain because the W200 is kind of a hybrid, so you're on your own. I did find one guy who had made it work, but you'll save yourself a lot of time and headaches if you forget about the W200 and buy a cheap wireless card. That was my solution.