I remember reading about this problem a long while ago and was able to take the steps to avoid it. However my brother is being plagued by it.
The problem is that he is getting a ton of pop-up ads whenever he leaves himself logged in. Now these aren't the normal popup ads that use your internet browser. These are the one being sent via a networking protocall. The look similar to the window you would get if someone in your net work used the "net send <blah blah blah>" command.
Anyone remember/know how to prevent these from occuring (besides logging out).