My Comand Sat Nav has decided to stop working on my 2005 E220 Estate. It says there is no disc inserted. The disc looks fine and it works in my friends Merc. I've tried his disc but get the same message. I've tried disconnecting all the cables and reconnecting but the problem remains. I have also tried a lens cleaner but had no luck there either. Does anyone know a good electronics person capable of repairing the unit? I am guessing that the lens reader or whatever it is called needs replacing.