wewmbw

I hope this is the right forum for this. I have a 2006 CL500 that I cannot get the Navigation working. I inherited this car last year. When I hit the Navi button on the console I get a NAV loading message on the display. After about 5 to 10 minutes I get a message NAV DVD not present insert disk. The disk is inserted. It is the original factory DVD that came with the car. I have cleaned the DVD and see no scratches. I have also tried changing the DVD reader in the truck with a different one I got off EBAY and still get the same results. Has anyone seen this problem? I really don't want to take it to the dealer for this. The battery at one time before I got the car had died and was replaced. Does anything need to be reset after battery replacement for the Navigation to work?

Thanks