Ad-aware can clean up the mess that's on your computer, but without a popup blocker, you get re-infected easier unless you pay REALLY close attention. The popup blocker won't do much to stop the ones that occur as a result of being infected. I'm pretty careful, and I still occasionally accidentally get something. Usually, you're typing away in another browser window, or MS Word or something, and a popup springs to the front, you hit the space bar, which answers yes to one of their installation requests, then you're hooked. Some of them install several.