2007 Buick Lucerne CXS NAVIGATION...?

The above stated CXS When I bought it 3 years ago had window tinting on the sides and rear window, Having that on the rear window disables the regular function of navigation.... Even so the screen still worked but just would not show accurate position and so forth. Trying to remove the window tint from the rear window was extremely difficult and I had the rear window replaced. It is the correct rear window But now instead of showing An incorrect map The screen will just say checking checking disk and from time to time It will state something about the disk being turned over... I will remove the nav disk and flip it over and whatever it never changes.
Is there a way to reboot the navigation on this car?
Thank you!