My Hitachi PVR has completely frozen . By frozen I mean that it displays a still picture, but you are unable to change channels or access any other function. At the time it froze we were trying to go into the Guide to set a programme to record. For a few days prior to this the device had been intermittently hanging when we tried to set recordings, but the problem was always resolved by turning it off at the mains, and then restarting. However on this occasion turning it off and on at the mains doesn't have any effect - it just goes back to the frozen picture. When you turn it off and on it appears to boot up as normal and there are not obvious warning messages on the display.