here is alink to lavasoft, they have aprogram that is called adaware
it will remove al the adware from your computer. is free and safe to use. sometime norton dont recognice adware and remove it. this found it. also do the uptate for windows xp, the security packs, amybe some site have hijacked your brouser or installed any program while you visited the malicuous site.
try it is free, also configure it to check your cookies and favorites for any malicious cookie.