The latest free edition of AVG 8.0 now sees an updated version of the old reliable Ewido adware blaster there since Grisoft bought that out. CCleaner is one way of freeing up a few hundred meg of drive space as well as clean out the IE history there.
The stickies will point out quite a few other anvirus programs as well as tools like HiJack This, firewalls like Comodo and Jetico Personal. Then there are special removers for certain lists of viruses Grisoft, Symantec, Trend Micro, and other software companies provide separate from their free and retail programs.