The TV settings will not effect the Navigation Drive. I suggest you pull the power from both the board monitor and the navigation drive. Give them 5min of no power.
Then power the system up and see what happens. after this try a firmware update as this will reset the system back to defaults...
let us know how you go...
This happened to me when I upgraded my monitor from 4:3 to 16:9 and I didn't change the computer from MK3 to 4 yet. the MK3 was still booting in 4:3 mode, but after a power cycle, all was good.

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X5 2001 4.4i E53