Need Help to play a new game in my PSP

Hey guys,
Actually i need any advice how to play a new game like NBA 2k12, PES 2011 in my PSP
Right now, i use 639 PRO-B firmware
It works for NBA 2k11
But everytime i put any new game (NBA 2k12, PES 2011) to my PSP
it always said the game can’t be started
Anyone can help me to solve this problem?
Thanks
Answer #1
Answer #2
What kind of PSP do you have? 1000, 2000, 3000? and I can tell you more.
Answer #3
my psp is 2000 slim