The day i purchesed the game i played it for about 30 minutes and it froze i had to cut the power to the PS as it would not switch off. The next day i played the game again and once again it froze i had to cut the power again now when i tried to load the game up again i get a message stating "An error occured during the start operation" i brought the game back to my local store and got it replaced but i am still experiancing the same problems with the new disk?

Has anyone any idea why this might be happening?