Do you see SuperFish.dll loaded into Internet Explorer or SimilarProducts listed in the Add/Remove programs dialog?
So, what’s SimilarProducts? This quote from the SimilarProducts FAQ offers some more details:
WindowShopper/SimilarProducts is a browser add-on that uses Superfish visual search technology to display deals and similar items for any product online. Once installed, it will present a See Similar icon next to product images on thousands of online stores in the US, UK, Germany, France or Australia.