Hacked by a browser
This happened to a friend of mine very recently. The browser had a new search bar, and the web page always opened up at lop.com. Damn thing, was the hardest to remove. Adaware and Spybot both could not remove it. Hijackthis removed the software, but it kept coming back. Since I did not have further time, the friend runs Hijack this occassionally but the damn software is still on his sometime. One of these days I will have a look at it.
First of all, I dont download crappy chat software of web sites, and try em, like my friend does. He uses the laptop solely for chatting. Second he did not have SP2 installed. Third he uses IE. Third strike, and you're out. And still I havent been able to convince him to switch to firefox. These people are just toooo lazy!