I was driving home today and taking a particlar not quick, but sharp 90 degree right corner ... I noticed the NAV screen reset on me.

Yup... reset.

The NAV screen looked like it turned off for a split second then turned back on again... I got the whole BMW version number thing and I had to push the the idiot accept screen again...

Really odd/wierd.

Sounds like your whole entire nav system is broken! Want to sell it? :)

Seriously, though, it's probably just a small short somewhere. My cell phone kept resetting itself a few months ago because a screw was not fully tight. You can probalby get it fixed if you can make the problem reproduce itself.