First off download this free virus scan(
http://free.grisoft.com/ww.download?prd=afe) and delete all the virus crap you have, and take off norton or any other security package you have cause again it doesn't do shit. Next you should be able to install those Windows Service Pack 2 or 3 to run that
version of iTunes. After you have completed these two steps, tell me if it works or not and i will help you from there