Audio Systems: Mercedes stereo lock up, e430, access code

Question
Help,
Was listining to radio in my 2001 E430, and tried to use "UP" arrow to change station and the radio locked up.  I can not do anything, change station, volume or turn unit off.  The screen stays lit with the last station,  even after the car is stopped and key removed.  Can you help?
Thanks

Answer
Joe,
If the stereo is an anti-theft unit you will need to access code before you do the following. After you have the access code, disconnect the battery to see if resetting the processor in the stereo will make the stereo work normal again. In most cases this will help, if not your stereo will need to be serviced.

TOM,
T&D ELECTRONICS
tdeser@zoominternet.net