AVG   (Free)

(Recommended)

Avast! (Free)

PCTools (Free)

BitDefender (Free)

AdAware (Free)

(Recommended)

SpyBot (Free)

(Recommended)

HighJack (Free)

(Requires experience)

Mozilla Firefox (Free)

(Recommanded)

Opera (Free)

(Free with ads, but still good software)

TweakVista