I run both Adaware and Spybot. I run Spybot and CWshredder on my wife’s computer, plus a suit of other spyware tools on both. The game demo download sites are some of the worst offenders. My son hasn’t found a game demo he hasn’t tried.
I would recommend Spybot as a first line of defense. It is a free program and the forums are heads above the rest as far as help and support. While the program is free, it does ask for donations - if you use it, please make one. I did and do not regret it at all. It take money to supprt the site and the work the folks do over there.
One thing that people do not do - after running the spyware programs, you MUST, I REPEAT, MUST delete ALL file in Temp folders. It also doesn’t hurt to clear the cache. Many of the programs stick a reinstalling exe in the temp folders and will reinstall the program. Deleting the temp files will stop this.
I have been on the net since it was text only and it getting more dangerous everyday. You MUST defend yourself 24/7 or you will end up with all kinds of crap on your computer. Keep you anti-virus software and spyware up to date. It only takes a couple of minutes, but it can save you days while you reformat and reinstall.