I'm using a FREE program called AVG 6.0, and it caught 5 virus's that Norton missed somehow. My whole system runs better now. AVG will even heal, quarrantine or get rid of the virus, depending on what it is. They offer it free to individuals, but you have to pay if you are a business or corp.
Check it out. I have no connection to this company, other than I found the product to actually work!
http://free.grisoft.com/freeweb.php/doc/2/
Actually, I think I got the info from somebody on this board!
Thanks, Andy