Norton products will not block ad/spyware pests. For this you need Adaware AND Spybot-S&D - yes BOTH - they complement each other. They'll remove most scumware & both have a backup feature so if anything should go wrong you can always restore the deletions. Also consider installing another program, SpywareBlaster, to prevent scum from entering your PC in the first place.
To download - Adaware - click here - Spybot-S&D - click here - SpywareBlaster -click here . All the programs are freeware. Remember to check for UPDATES regularly & BEFORE scanning for the first time.
Also visit this site & have a good read - click here - about dealing with unwanted spyware and parasites.