Was it your box that had Wurld on it? If it was, there may still be some vulnerability we don't know about.
Try downloading the Spyware Blaster from the IBox. It is a neat little program. It doesn't run in the background or even search. What it does is set "Kill Bits" in your computer that makes spyware and some popups think that they have already installed themselves so they won't do it again.