Disk not loading?

I've been playing Final Fantasy XIII a lot lately. I just got my PS3 last Christmas, a 220 GB slim, and FF13 has been the only game I've had money to buy, so I really don't have any other games.

It's been working fine recently, but it's started acting weird today. The disk comes up and loads like normal. The title screen comes up, and I go to load a file. The file loads, but when it's loading the actual game, it stays on the loading screen forever. I've waited upwards of 5-6 minutes for it to load, but it won't. Once, the music came on for about 5 seconds, then stopped.

I tried loading a different file, but no luck. What can I do to make it load properly again?

The disk has no scratches on it. Except for one tiny scratch that isn't too deep near the bottom.

I got it to load a little bit ago, and it's doing fine at the moment, but this is sort of an on and off issue.

I Bought my new version xbox360 in black colour , and gaming with hardisc 500gb . I keep looking for Final Fantasy XIII for 2month since i bought my xbox360 , i'm just like crazy of it .. at last i get my FFXIII , but it come up with 3 file (3 disc) and when i finished my Disc 1 , it ask me to change to FFXIII Disc 2 ?? and ?? i'm stucking there.. and when i back to xbox home and get into FFXIII disc 2 and i load the game , it ask change to FFXIII Disc 1 ?? omg.... u got to help me !!! The only reason i bought my Xbox360 is to ply my Final Fantasy XIII and carry on XIII - 2 , XIII -3 is coming soon ~!!