I'd suggest you try Spybot-S&D I find it v good at detecting spyware, adware, and other unnecessary stuff that websites download when we are surfing and going about our business on the web. A google (other search engines are available) search will find a download site - its fairly intuitive to use. It might not fix all your problems and you may be surprised about the amount of other stuff on your machine.
Picking up other comments - I'd agree Norton isn't best Macafee is better and I'd suggest firefox rather than IE - I also tend to clear cookies at the end of sessions.
Good luck
John