HijackThis is a program that can be used to quickly spot home page hijackers and startup programs that you do not want to start automatically. This program is a not anti-virus program, but rather a enumerator that lists programs that are starting up automatically on your computer as well as other configuration information that is commonly hijacked.

Trend Micro RootkitBuster is a program that will scan your computer for Rootkits.  This scanner will scan for rootkits that are using the latest technology including Master Boot Record (MBR) infections.