I have one PC in the office that randomly opens a music stream to a radio station. My assumption is that the user has visited this station before and clicked on something but he says he hasn't. Anyway what it does is start streaming across the internet at random times throughout the day. It doesn't open a window or show anything on the screen, but if you can hear it and if you bring up task manager, there is an instance if iexplore.exe running. Kill it and the music goes away. It comes back between 5 minutes and 60 minutes though. I have run Hijack this and a spyware program and nothing shows up. There are no add-ons that I can see in IE that would cause this.