Originally posted by: dman
Adaware is free (well one is) and does an ok job for what it's designed for.
Between that and Spybot Search and Destroy, and some of the other tools you can find on the spywareinfo.com forums and site you can keep your system pretty clean.
Use Hijack This, for example, it might find some tasks that are reinstalling the virus software after adware/spyware info finds them. You can do it manually too, check the MSCONFIG prog and see the startup tasks, a lot of time there is a program like kkxszz.exe (a gibberish name) that is running and reinstalling the spyware stuff (adaware doesn't catch them).
Also, check the other FREE program spywareblaster @
http://www.wildersecurity.net/spywareblaster.html
It goes through and prevents a lot of the activex scripts that are out there from working so spyware doesn't get installed (you don't even get prompted). However, it's an ongoing battle so you have to be smart and no what to click yes and no on when you surf and you need to run the tools every now and then to make sure nothing slipped through the cracks or got by an exploit.
Or you can pay for a commercial spyware tool like some of the companies are now starting to offer that auto-update and help remove stuff.
[edit]: And as said above, Adaware and Spybot both will flag cookies as spyware, you can prevent cookies from being installed a swell but that may break your access to some sites so I choose not to worry about the cookies (and delete the flagged ones when I run the tools).