I was having the same issue with the game stalling on launch. I even turned off DEP and had the issues still. My system is Win 7 64 bit with an AMD FIrePro Mobility Card. I read on the Steam forum that some folks got it to work by setting the Compatibility Mode to Win 98/ME. I tried this and it seems to solve the problem for me. Hopefully this will help others.

yeah not so much on any of these fixes.... no game for me

Also tried all those things..

For me the Compatibility mode as 98/ME worked, but only AFTER I had installed the latest ffdshow (found on sourceforge via a quick google ).

Mysterious.