I installed and used Spybot on a couple of computers. Spybot.com. Found and removed alot of stuff. OldTrader
I have both spybot and lavasoft's ad-aware. I think spybot is a better at detecting offending programs/spyware.
It appears some people claim Spybot itself has spyware components and/or causes your system to malfunction. The pattern of the product reviews on CNET is suspicious, lots of rave reviews presenting Spybot as the best tool out there but also a fair amount of reviewers guarding against the hype and the problems the software causes. I haven't tried it yet but I for one know that it's useless against adware.searchcounter (see my thread on this)
I was told the one instance that you cannot retrieve info was when you reformatted your hard drive. But, check with an expert.