A strange development today. I have a PIN number set up on my phone for security. Usually, when I slide open the lock screen, the the next screen shows "Enter PIN to unlock" . Today, the keypad flashes on and off quickly, but does not display long enough to enter the PIN. I have tried restarting several times, but get the same result. I use SWYPE as my default keyboard. I have made no recent changes nor new apps. Any ideas?? Thanks.