Battery, died, I put in the code to unlock the radio. It initially worked I turn off the car. When I turn the radio back on the cd player isn't accepting any cd, the radio is showing the channels but no station is playing. The controls on the steering wheel no longer works. The DVD works, the 6-cd changer is working and led lights on the panel is working. What can be the cause and can it be corrected without taking it to the dealer?