Superantispyware, The best anti-spyware program on the planet today and it's free. It's found stuff the other programs like Ad-aware, etc. could never dream of finding.
http://www.superantispyware.com/

spywareterminator, Maybe not as good as Super but a close second, And if you have Windows 2000 or XP it comes with free Anti Virus protection and awesome protection at that. I have Win98 unfortunatly so all i get is the spyware protection. but i installed this on a friends computer who was having problems and this and Super together worked wonders.
http://www.spywareterminator.com/

ProcessExplorer, Another must have, It ends processes like you would do with the Ctrl Alt Del method but works better. It can get those tricky virus or spyware apps to end when they won't end the other way, and i think it has other features.
http://www.sysinternals.com/Utilitie...sExplorer.html

FreeRAM XP Pro, Will help free up Memory, A must for Win98 users.
http://www.yourwaresolutions.com/