It's freezing on me.

I've gotten to Act IV without it freezing once, and now I can't play 10 minutes without getting a little disc/question mark flashing in the upper left-hand corner of the screen. Once that has began flashing, the whole game except that **** freezes and the only thing I can do is go into the Quit Game, Controller Settings, Turn Off the System and Turn Off the Controller menu. And when I choose Quit Game and Yes, the screen goes black and freezes. So I have to turn off the PS3 with the On/Off button. With my hands.

On the IGN forum, they say you just have to uninstall the game from the harddrive and then it's all good again. So I did that. During the install it freezed again. The ****er. I deleted it again and installed it sucessfully, but the problem is still there.
 
Do I have to get a new disc? Do I have to get my PS3 fixed?
 
Searching the internet, I found at that not many people have this problem. I can still play other games and movies, but some of the other people with this problem can't play anything. So I assume it's the CD that is faulty for me, and the Blu-ray drive for them?
 
There are no scratches on my disc, no dirt or fingerprints. It's ****ing clean. When it has been inside the PS3 for a while and you look at the bottom of the disc from an angle, it looks like it has smelted a bit. It's like.. warped.
 
It's kind of aggrevating to have come so far and gotten so involved in the story and then not be able to play.
 
Anyone else with this problem?