I have a 2005 C320 4matic with the stock radio, no navigation. I have seen similar problems while searching this forum, but not mine specifically. I was driving today with all audio functions performing perfectly. I stopped at the drycleaners for about two minutes, and when I started the car back up the radio lit up, but no sound came out. Thinking it was a problem with the FM station, I switched stations, still no sound. I then noticed that the softkey for my Sirius was no longer available. I tried both the 6 disc CDC and single disc CD, but both returned a message saying NO CD. Has anyone experienced this issue, or have an idea of how I can fix this problem?