I am currently having some problems, i will first list the equipment i am using

PS2 Slim version (7000) series
PS1 memory card (8mb)
PS1 GameShark v4.0
Gundam Battle Assualt 2 (mint condition)

Heres whats happening, i am currently trying to use Gameshark to unlock some characters from this game, i already have the codes so thats not the problem. The issue i am having is that this game does not want to load completely after the disk swap. After i swap the gameshark out and load the game it only loads the intro video and does not allow me to enter the title screen even after pressing start. Ive even gone as far as to trying to start the game without codes, and still i get the same result. The strange thing is that i tried testing it out on the game preceding that one which is "Gundam Battle Assualt" and this game works perfectly in harmony with the Gameshark.

What should i do???