This website shows you various system utilities that you can use to make your PC perform “like new” again.
Anti-Spyware Tools
Spybot S&D
Safer-Networking (freeware)Download: http://www.safer-networking.org/en/download/index.html (direct download)
Description: Spybot S&D is a "virus scanner" for adware/spyware, including a real-time protection.
Ad-Aware
Lavasoft (freeware for noncommercial use)Download: http://www.lavasoft.de/support/download/
Description: AdAware, "virus scanner" for adware/spyware, one of the best; requires next to no knowledge for use, regularly updated, free version is powerful enough to be useful.