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Spybot S&D is as honest as the winter is long, may be a little “dated”, but is still actively supported and updated, and I wouldn’t be without it, either, despite having a few other more “whizzy” applications.
It must be one of the more trusted applications around, it’s been available for ages, has always been free or by donation, and the help files and forum appear to be very helpful.

Unlike AdAware 2007.