Black Ops freezing/glitched?

When i first got this game, it worked perfectly (on my ps3). now its all glitched, the campaign is glitched, the Dialogue rarely comes on in the campaign and zombies, when it does like 5 people talk at the same time and its out of order, sometimes your gun disappears but you can shoot it, the scope on the crossbow doesn't have the cross hair ( the black part when zooming in), zombies offline freezes halfway during the loading screen. But you can still hear the characters talk, but after the talking stops the game completely freezes(both split screen and solo) and wont let me play. the main menu music wont start until you wait a while. Can any one help me? Like give me ways to fix it? The disk has no smudges, and only a few small scratches. Maybe its the ps3? Please help! Id like to play zombies again!