PS button isn't working.

Hello. I have a problem with my PSP 3000's PS button. I've tried to press it several times and it still wouldn't go to the "Quit Game?" screen, and there will be times when I have no choice but to remove the battery and place it back in, but I don't want to risk damaging the memory card.

I've tried opening the case and wiping off any dust that got caught in my PSP and it still wouldn't work.

Any solutions please? Thanks.