I know of two free thing that work awesome for pop-up, spyware, ad ware. Here are the links. Oh, if you do a search, I think this was discussed and my have some more info for you.
This is ad-aware. You need to run this everyonce in a while and delete the spyware and ad ware.
ad-aware from pc magazine
And this is the google toolbar. It is the best search toolbar out there. It can highlight text in a web page, find words, auto fill forms, stop pop-ups, search the web, all kinds of stuff. The best part, it doesn't put a bunch of crap on your pc when you install in. Just pick the one that doesn't send info out for research and you'll be good..... you'll see what I mean if you read the prompts on install.
google toolbar