Spybot does pickup adware and other insfestation on FF though. FF, once set, is supposed to not let in third party cookes, but I just set it and what appears to be third party cookies still appear in the FF cookies memory (tools, options. FF also has a bad prog blocker, and of course its pop up blocker.
The adware (and usage tracks) that spybot detects, and I have fixed, does get moved to recovery. Don't know if it means anything, but I notice that while using only FF, sometimes data collects in the IE folder (I just clear it out, so have not looked it over to see exactly what it was).
FF has some sort of a built in program that is supposed to immunize the effects of such adware. Adware-se and my Xsoft very rarely pick-up and adware when I use FF, but really do not know why.
Don't know how much help this is, but thought I'd shoot it your way.
Diligent