Made the fatal mistake of pressing the red button on BBC tonight.
My Samsung 2100 (second one I've had within six weeks due to other apparent fault) froze completely. Did the usual and whipped out the mains cord. But instead of the normal re-boot, it came back showing a zero in the channel window and flashed a message on screen saying I wasn't subscribed to any channels. Attempts to change channel failed, thus proving what it was saying was true.
As per usual, I pulled out the card from the set-top box, gave it a wipe and re-booted again. Same thing happened. Whipped out the mains again and left it half an hour. Surely that would clear it? No such luck. This time it's come on, showing zero in the window, but offering only a totally blue screen - and ignoring all attempts to change channel. Good job I didn't want to watch cable TV or anything.
Annoyingly, it's also degraded the signal on my terrestrial channels, which I guess I must receive through the box. Sigh. Back on to Customer Services tomorrow. I'll have to get them on a speed-dial soon.