SpyBot is supposed to detect and remove PurityScan, and SpyBot is free. You can download it
here , and don't forget to run the update to get the latest reference files.
SpyBot doesn't detect all the tracking cookies that AdAware does, but it does seem to catch more of this type of threat. I use both.
You might also be interested in reading
this manual removal info from Pest Patrol's site.
p.s. Just noticed this on SpyBot's site re SpyFerret:
"This software is infringing our copyright. Please do not use it!
Evidence: installs one file that is copyrighted by myself (Wsock.dll, which is an exact copy of my file Tools.dll. Threats are also named exactly the same way, including some invented threats."
