Key Of Heaven Issue

[kithop]

Hi everyone! i've transferred the iso of key of heaven into my computer (windows 8) but the game doesn't work: when i start a new game, it's very laggish and when the initial video ends, the screen goes completely white and the only thing i can see are the subtitles and the statistic of the pg like life, chi , map etc... I also have patapon on ppsspp and it works perfectly. How can i solve this problem?