Now I don't mean to be rude, or try to rubbish your choices but...
Take a look here
and then go http://spybot.safer-networking.de/en/index.html
Spybot really is 'the daddy' of all anti spyware programs, and now even has a system monitor (teatimer) that looks for things trying to install themselves. it makes you aware of spyware trying to be downloaded, makes you aware of programs trying to install themselves.
updates are free (as is the program, not shareware, not trial, not restricted (like ad-aware).)