I do computer service but I have no experience with this particular device. My customer (who, for a change, is fairly computer-savvy) swears up and down that she never assigned a PIN. The tablet used to just go into her sign-in screen, but now it demands a PIN. She says she never assigned one. There seems to be no way out of the PIN screen.  Under each number there are three letters but there seems no way to switch to alpha. I can get to the notification panel/pinch zoom/power-off menu -- but any of the buttons there which might be helpful (for example, SETTINGS) do not do anything.  On the power-off menu, the "restart" button doesn't do anything either.  I can't get out of the lock screen to anywhere else.  I've tried all kinds of key combinations to achieve a hard reset and nothing works.  Any ideas?