Hi all, new here!!

I've got a 2001 M5 with a mark 3 Sat Nav system, I've had a few problems with the battery going flat sometimes when I leave it. The other day it was flat, used jump leads, got it started, drove home and the radio went off and the screen went black.

When I got home I restarted the car and the display came back on, but this time the display has completely changed. It is now has a blue background and a very basic font. Similar to an 80's nintendo game. Navigation is also missing from the menu.

Any suggestions, it looks awful!!