My LG LAN-9600R DVD navigation system crashes. I start the unit up press agree on the screen for the sat nav and then I either click on a radio station and the unit will freeze so you can't turn it off or do anything with it. The unit freezes after a different amount of time each time it is switched on if it turns on in the 1st place. The unit seems tempermental, is there any idea what this could be (update/wiring etc.)?