i bought gt4 the 1st day it came out and about 2 months later it stopped working, i couldnt repair the disc in anyway, so a bought another new copy and same thing 1 month later, and just about a week ago i bought a copy from gamestop and it worked great until today, then i went in and traded it for another copy which does not work and the crazy thing is that all of my other games work fine in my ps2. any thoughts!?