Whenever I try to enter Gamorrah, I get through the doors and can see the area, but I am stuck in place and can't move. It seems like the same thing that happens before an NPC comes to tell take your weapons in the other casino's, but in this case, no NPC, just stuck there and have to reload a saved game. I can't use the pip-boy, I can't draw a gun, I can't talk to my companions. All I can do is spin and crouch and jump. I have rebooted, defraged steam cache, restarted the game, checked/updated all drivers, defraged/optimised registry, verified local files. Any help?

Win7 Ultimate-64bit
AMD X4 PhenomII 940
4GB memory in ganged mode
4870HD AMD video card