Hi,
There is a very, very good, free program I use; SpyWare Blaster. This program stops spyware, etc, from getting into the computer in the first place; doesn't require scans. It integrates with the browser, such as Internet Explorer, placing known definitions in Restricted Sites. It has weekly downloads, just like Norton, AVG, etc.
Since using SpyWare Blaster, I have not had one single Spyware issue, doing scans with AdAware. I finally uninstalled SpyBot......don't need it; but still have AdAware, just in case.
You can get it at:
http://www.javacoolsoftware.com/sbdownload.html
Microsoft also has an anti-Spyware program, which I haven't tried....don't need it.