Billy,

I use Adaware SE Plus ($26.96) http://www.lavasoftusa.com/software/adawareplus/
The BIG advantage of going with the $26.96 version of Adaware is that it includes real time monitoring. The free version of Adaware doesn't include this.

Another program which is HIGHLY RECOMMENDED and FREE is:
Spybot: http://www.safer-networking.org/en/index.html