I share your lament, Mat. I get the same shit on mine from time to time.
My first thoughts were that it was some pop-up my eye did not catch, or a built-in advertisement being played through one of my programs. Upon inspection, I found no such things.
Computer ghosts.
I remember I did
something once that seemed to shut it up. Cannot recall what. TO GOOGLE! *zoom*
Edit: Possible solutions...
http://answers.yahoo.com/question/in...9082730AAnbd9o
http://social.microsoft.com/Forums/e...0-77160b41d0e7
http://www.computing.net/answers/sec...rus/20952.html