On holiday at the moment and my command on a 2007 r class is frozen. From memory it is version 2.5. The command screen in stuck on the audio screen. None of the button on the command unit are responding. Basically I can't do anything with it. I was depending on the sat nav to get me around and basically don't have clue when it comes to roads in the area I am in. Four kids in the back are not helping. Anyone know how I can reset the unit.