Game won't launch

[Cowpox]

I've tried everything in the pinned thread and nothing has worked. The game simply won't launch, steam tells me that I am ingame for about 10 seconds, maybe a bit less, and then says that I am not in a game any longer (my avatar becomes blue). A launcher or opening logo is never shown and when I check the task manager, UDK.exe *32bit opens for a little while and then closes for no reason. I have an nvidia card (GTX 580) and the latest drivers installed.

I have a later version of physX than the one that comes with the installers in the game files, that is the only reason I could think of as to why it is not working.