I have had this software for about 6 months now. I am extremely pleased with it. The main reason I purchased it at the time was it's BHO (browser helper object) capabilities. These BHO's hijack your browser and homepage, making web surfing a complete nightmare. In the event of installation of one of these, the program instanly alerts you and asks if you would like to remove it. It is a very powerful tool that in my opinion is unfortunately necessary for internet usage today. This company is also very diligent with news, information and an important leader in combating the spyware problem. It does also find adware and spyware that other programs seem to miss.
Spybot is an excellent program also, but is only as advanced as it's researchers. It looks specifically for the files by name, (ie: Brilliant Digital), instead of identifing a spy file itself. It is absolutely necessary to check for updates at least weekly and run the immunize feature a couple of times a month.
I have rebuilt at least 3 hard drives from scratch, and have run across every disaster you can imagine. It seems like more work to maintain a computer sometimes than it is worth.
Also, take a look at some of the Webroot products.
www.webroot.com. I have also purchased the spy sweeper ( I personally think this is by far the best of the best out there, and I've tried them all), as well as the pop-up washer. They both have free trial periods of thirty days.
These products seem to have solved the issue for me. In total I believe I've spent maybe $150.00US on all. I've definitely received my money's worth and then some.
Lastly, Microsoft's web site has a feature called Microsoft Security Baseline Analyzer. It is located in the security section. I don't remember exactly where, sorry, but it's easy to find. It's free, very quick and it analyzes your whole system and shows you exactly where your hard drive weaknesses are. It's very informative and helpful. It thoroughly explains all it's findings and offers help and suggestions throughout.
Hopefully some of this will be of some help to you!! Best of Luck!!