Psp games Freezing before i can play.?

Hey i have a problem with a psp i try to load up Prince of Persia Revelations and it goes all good up until after the final loading sequence it gets stuck on this castle clip.And im running CFW 6.39 me-2 and when i open up the vsh menu to change it from the Oe Isofs option and to the m33 driver one i get a small amount more loading then the same outcome the psp powers off.So any HELPFUL answers thanks,and yes there is a 6.39 me-4 cfw available by neur0n and some1 but i dont want it to be honest same features.Again thanks for any help i get,and i OWN Prince of Persia Revelations so i can LEGALLY make an iso/cso copy of so long as i dont distribute it(I never do) Thats for yahoo if they try to remove the question.A quick answer would be great,also :P the umd is really my cousins so i cant use it.