Before trying my suggestion do backup the Registry, if you don't understand what or where the registry is do a "Google" &/or favorite search engine search for information on the Windows Registry. Don't attempt if time is short,etc, this is certainly not a quick fix. Do a search for spyware removal tools, information, etc. In other words research the subject before trying to solve this specific problem

A good spyware program that will tell you exactly where a spyware has inserted itself i.e. the exact registry key, cookie. etc, is called SpyBouncer and at least for now you can use this information to remove said registry key by opening in Run(Click Start, Click Run, type regedit) regedit and going to the exact registry key, deleting it, etc. When through with regedit, close any opened keys, exit regedit, reboot and rerun the deep scan option in SpyBouncer which shouldn't find any problems.

There are two completely free programs Ad-aware and Spybot Search&Destory, along with xcleaner_free. Do note that many of the programs advertising themselves as "free" are only free for the deep scan and require registration(translation purchase) to remove any found problems. A possible reason for the lack of a trail removal period is that much of what spyware does, it does to the registry and so it is possible to manually remove them which doesn't require a software program to do so.