Subscriber JPB wrote to report about what was really happening in his problem discussed in Windows Media Player and Windows 7:
I finally figured it out. It took a lot of research. There was nothing I could find in the registry or anywhere that was triggering this.
Finally, I discovered it — it was my Logitech G15 keyboard. The one with the LCD screen. For some reason it uses windows media player. Needless to say I was able to kill it from within the G15 software.
Check out the Logitech keyboards at Amazon.