So let me make sure I am understanding you correctly, you already have an 80MT disc installed but you wanna FORCE reinstall it?
If so then do this... Go into your NAV MENU and select "System Options", then select "Language". Change your language to either French or Spanish.. The unit will reboot and reinstall the map software in that language you selected.... Then once it has finished you can go back thru the menus to change back to ENGLISH. Just make sure you remember where the menus are because remember they will be in a different language when you first update.
This method worked pe