Anytime I try to open up anything windows related,(My Computer, My Documents, any folders with the folder icon), my computer stops like it's thinking or something, and then it refreshes my desktop. This happens when i try to access it from the start menu as well. System Restore does the same thing. I scanned for viruses and such and found 2, one called js.cassandra and bot.xpon(or something like that). I also found a something called hacktool. I deleted all of that but now my system still doesn't work as well as it used to, like opening folders. I think the hacker changed something in my registry or something that binded double-clicking any window's folder in explorer to refresh my screen or something. however, if i open up My Computer and the files from Deepnet Explorer, (which is like IE), i can access the files w/o a problem. I'm also having some trouble getting online. any suggestions on how to fix it? i'm thinking that just reinstalling XP should fix it, but I want to do that as a last resort.

Try accessing System Restore from either safe mode or 'Safe Mode with Command prompt'... type in: %systemroot%\system32\restore\rstrui.exe