I swear by Spybot Search and Destroy and HijackThis. Although we build computers, repair them and kill spyware etc, we have installed more versions of Spybot Search & Destroy on computers than Windows OS.
My website has a Windows based FREE (FREE means FREE!) scan solution for Spyware and it seems to work very well.
For anti-virus then you need to try Dr Web Cureit! it is free to download and does not install. Has to be downloaded everytime you suspect you have a virus infection, owing to the fact that it is updated everytime a new addition is added to their wild list. For more information on these and other solutions give our website a view. It is there to help!
Regards
duenna
http://www.dmscs.co.uk