I have just recently bought Fallout: New Vegas for my PC (as I loved it on the Xbox) and I am able to load up the game alright, I've tried re-validating my game and the same thing still occurs.

Every time I leave Doc Mitchell's house in the beginning of the game, the game crashes and a pop-up appears telling me "Fallout NV has stopped running, Windows will close the program and notify you if a solution is found".

It has done this every time I've tried to leave.

Help would be greatly appreciated.