PSP 2000 start button does not work. help! >_<

hi! i got a problem with my psp 2000. The start button does not work. Instead i use the "ON and HOLD" switch to use the "start function". i guess its kinda unusual how that happened but it really did. I dont really know what might be the problem. the problem might be from the software or maybe from the hardware. Anyway, is there I can fix this? Its really annoying to use the method of switching to "HOLD" and then switching to "ON" just to start a game. Well thanks in advance! ^^