This problem has all the indications you already had a nasty virus/worm, I have been running SP2 for over a month now with no problems at all and have been running my internet connection behind a 3rd party firewall/proxy server. Do you have the latest AV? If not you are or have been vulnerable to some nasty that has got in to your PC. Have you backed up data? Can you do a full system restore? One way or another you need to clean up your PC, and an old (more than 13 months) virus checker won't do it.