Having trouble with your psp???

hey!!! i just got my second psp second hand,
i was playing it for like 30mins then when i went to play on it the next day it started to play up.

basically when-ever i press start the screen will go black for around 10-30 seconds before appearing back, but then the controls will freeze and i have to press 'home' and when it asks if i wanna quit i select 'no' to get it working again.
but sometimes the screen will start randomly switching between the different light settings and just black out for yet another 10-30 seconds,

anything to suggest???? i couldnt stand buying a third one : (