I've had this unit for many years and it has been totally reliable. I've just downloaded the latest update. When I unplugged from the computer, I was asked for my passcode. For some reason I put in the wrong one. Now, when I switch the unit on, the driving advice comes on. When that disappears and the screen pops up for me to enter my code. Before I can do this, the machine shuts down. I've tried this several times. I do rely on this unit, so any advice would be very gratefully received. Thanks.