For a long time I didn't have a PIN for my tablet but circumstances have now made it necessary. When I first got the thing, the lock screen would come up every time the display timed out or was turned off but I deactivated that function. But, now that I want it back, I can only get the lock/PIN screen when the device is powered up. When the screen times out and I bring it back up, no lock screen. How do I get that back? I want it locked every time the screen goes off from timing out or whatever.