Navi "Last Destinations" "frozen" problem. 2007 X5 3D

[NDEHONE]

As of 2 weeks my navi always wants to take me to "my office" as the last destination. Even if I just stop at McD for a coffee, the navi resets its destination to "my office".
Also the last destinations are not deleteable. I delete every single one of them while driving, but as soon as I off and on the engine, whoops they have all come back.
Effectively my "last destinations" has "frozen". The new ones will not enter and the old ones will not go.
Any ideas???
How do I reboot a navi?
CHEERS NIGEL

[NDEHONE]

Ok I have to update this. It is fixed.
First off things got worse. The video screen went grey. Then dropped to "default colours". The reason was that the navi had completely died.
I took it first here: http://www.anusic.de/. This guy is the BEST. He is in Frankfurt Germany. I have been there before. He did a quick diagnosis and tole me that the "video module" was bad. Charged me nothing. And suggested getting a full diagnosos from BWM. ( BAD IDEA ).
BWM Charged me €100 for effectively nothing. They told me "the Video Module" was bad and a new NAVI costs €2600!! They also undid the battery and reconnected it. Arrghh. They forgot to recalibrate the Sun Roof (total €100 and they forgot!!)
I looked up new navis in ebay and found one here: http://www.mickscar.de/ He is near Cologne.
This guy is also the best. BWM charged me €30 to take out and put in the navi. Two "Blaupunkt forks" and mick repaced the thing in 60 seconds!.
It seems that the onboard produces a video that it sends to the navi. The navi does his bit (if it is alive) and sends it back. In my case the "video module" was the navi. I guess the TV fits in there somewhere as well, but that was working and that is what stumped us at first when the diags said "Video Module dead".
Anyway Mick looks at the car clock, says its wrong, "they disconnected the battery". "er.. yes". "checked the sun roof"... Yep it only moves 5 cm. They forgot to recalibrate.
Key to ignition 1. PRess the sun roof switch up until its finished cycling the thing back and forth. Takes about 3 minutes. Fixed that.
Moral of the story. Do not go to your friendy. They charge loads of cash and screw up.
Oh and I also learnt how to set up a few navi things.
Key to IGN 1. Menu... Settings. now press and *hold* menu.... Lots of nice settings there.
Hope this helps someone.
Nigel