Is it a virus or spyware or both?

Black hats are jerks. White hats are coo', though.

For my machine, the best offense is a good defense. Being aware of what I download, using Firefox, and regular AV and anti-spyware checks keep my machine running in tip-top shape. The only thing that could make it better would be if I would switch to Linux and eliminate the threat entirely (well, mostly), but I'm not quite there yet.

edit: It's obvious from the replies that most of you lump everything bad that can happen to your computers to be the fault of "hackers." There's actually a lot of classifications. Hell, white hats don't even do bad stuff. They help out companies to improve their security.