PSP, multiple question

Hi everyone! I was wondering something. I've bought this psp( first model) to a guy in my town. Pretty good deal, but I've seen it's hacked( I think) and I need a update for the system to play tactic ogre and ragnarok tactics( that I just bought). What do I need to do to play my game without destroying my console!? Do I need to reformat the system, there wasn't that much only two games which he admitted he download on the internet. Any help would be appreciated!:)