Uncharted 2 loading problem please help?

I have been trying to play Uncharted 2, but each time I go onto the game the dagger appears at the bottom right of the screen as usual and then when it disappears everything goes black and stays black. So I press the playstation home button and click on quit game and this restarts my PS3. I have retried doing it over and over again several times and the same thing always happens. I have tried taking out the disc, cleaning it but still no gain. Can you please tell me if you have experienced anything similar with this game or any other game and how to fix it (if i can). There are no scratches on the disc, the disc looks as good as new. I have had the same thing happen before with this game but it usually only ever happens once and the next time I go onto it it works perfectly. But this time I just can't get it to work.