I have had this problem more than once, and from what I can tell it comes from unplugging headphones while playing music, talking on the phone or some combonation of all. What I have done to fix this is do just that, play music without headphones, plug them in, unplug them, play again etc. Just go through every possible combonation you can think of. Also if you use an fm transmitter that plugs into the docking port, then you need to use that in your tests as well. I can't tell you the right combination, cause I don't know excatly what it was to fix it, but this has happened to me twice, and I got sound back after both times.