Connect to [Only registered and activated users can see links. ] and update/reload the unit firmware [latest is v4.50, if it's already OB load it again], then check for further updates such as BT firmware. Hard reset again both before and after updates.

The battery is probably on the way out but they're cheap enough and i think the same one as 2 series. Many common Nokia batteries can be adapted with a little soldering for nuvi models: [Only registered and activated users can see links. ]. Check for a 99power . com video on youtube, they have very good guides for opening units safely. The 765 is a very well-featured robust unit, but they're all a bit long in the tooth now.