I've been playing New Vegas for over 40hours and encountered very little problems. Suddenly every time i now enter combat and encounter enemies it crashes. It's become unplayable. Anyone had the same - help!

Have you either tried loading an older save, or clearing the system cache? I know that having to do stuff like that svcks, but I have been playing under the impression that I will eventually get touched by the game breaking hand of fate at some point. Always keep several save files, rotate them, make sure to load old files after saving occasionally to make sure the file isn' corrupted. Only play for an hour or two at a time before turning off the console and restarting with a system cache clear. I have become paranoid and strange by playing this game, but anyway try clearing the system cache.

Yep, tried clearing the system cache, combat is still completely buggered. Just crashes immediately you encounter an enemy where ever i go. Unbelievably frustrating that a game can simply stop working like this. Fingers crossed there's a patch coming that will resolve. Thanks anyway.