IF YOU LIKE DROPPED YOUR PSP ONCE'S ON THE GROUND NOT HARD OR HIGH PLACE, JUST DROPPED, AND THEN MONTHS LATER IT STARTS ACTING UP,YOU WILL KNOW IF YOU HAVE THE STUCK KEY MODE,YOU WON'T BE ABLE 2 DO ANYTHING,THE KEY SIGN WILL APPEAR AND STAY.SO IF YOU LOOK AT THE RED SPOT THAT IS WHAT MAKES IT UNLOCK, THE SOLUTION IS A NO# 2 PENCIL,JUST DON'T PRESS 2 HARD OR YOU WILL HIT THE NEXT 1.
I TRIED SOLDERING IT BUT DID NOT WORK,SO JUST USE THE #2 PENCIL AND BLOW THE REST OF DUST OFF.
AND IF THIS HELPED YOU IN ANYWAY LEAVE A COMMENT PLEASE.:)