One other possibility: I don't remember the exact error message I got but unit would shut itself down repeatedly. Turned out to be a bad data card. Easy to check out if you have a card you know is good. (This was on a 376C).
Originally Posted by achesley
Problem happen as I just saved track file. Unit went blank and has " Software Missing " on screen. Tried taking batt off and reattaching, turning it off and on a few times. 'When I push the power button it sounds a little tone and the message " Software Missing " shows , then , blank.