+1 for Martian's imaging advice. There are some linux liveCDs floating around the web designed with that purpose in mind. You can even store the image on the same drive or a thumb drive and leave it in your desk drawer (I have an XP home image on a dual layer DVD, with Diablo 2 loaded~!
).
GOD, as far as undoing the damage the malware did, there really is no way to be sure you get it all. Heck, there is even no way to make sure that the malware is actually completely gone without starting from scratch. If there isn't any vital info on there I'd just nuke it, because you're not dealing with a spider, but a preteen godzilla.