L4D2 desktop crashing?

[Stuart]

Okay so each time I start up l4d2 it loads fine right up until the point where I load up the lobby for my local server.
I start the game and it gets to about half way on the loading and it just crashes me straight to my desktop without any type of error report.. ?

I use Windows 8 and I know some of you who are unsure about the OS will mock its compatibility but for me its never been the problem at all because it use to work perfectly before..

I reinstalled l4d2 on the 18th and ever since that update on November 20th i've been getting problems. Needless to say thats not for everyone.

I use a GTX 560ti OC with the latest Nvidia drivers 310.61.

I've checked the cache files of this game continuesly and each time it downloads some mystical file thats 7.3mb. A few others I know have been getting that each time they check their games cache.

If anyone else has had this problem please feel free to lend a hand cause this is driving me mad, so many problems with this game.