Unplug the box from the mains, wait 1 minutes, press and hold the backup button on the box then switch on at the mains (keeping backup button pressed), all four lights will light up on the front of the unit after approx 10 seconds, at this point you can stop pressing backup. A message will appear on the screen UPDATING SYSTEM SOFTWARE, leave it do it's thing for approx 10 minutes, this will hopefully fix your problem.
Regards
Vic
Vic Lloyd, February 2014