I recently got a PSP used from fleabay and it was listed as a having a broken screen. I replaced the screen, but now i noticed that the whenever i hit the home button in game to exit, no button responds to complete the exit. I can hit home again to exit out of the exit screen itself, but even when in the exit screen, any buttons I hit still seem to be registering in game as i can hear the sounds of say a punch or kick or footsteps for example. Its very wierd. Also the Start Key and Select Key never register when i press them. Volume control works as it should. I tried replacing the actual board that snaps onto the bottom of the lcd, and also replaced the button circuit board it plugs into. I also upgraded to 2.0 and same thing. I downgraded to 1.5 again and still same thing. I cannot see any physical damage to the mobo, ribbon to the button board or otherwise. Any ideas?