So give some info,
What version of game , If it DID work but now DOESNT work then something has changed.
Have you applied ANY patches AND SEEN THEM LAUNCH POST PATCH ?
Your on Win7 64 bit, Where is the game installed?
To be honest the symptoms sound like a poorly applied patch, that is what I assumed, I was wrong to assume anything.
I just reread your first post

I did the following things :
-reinstall the game
-reinstall STEAM
-clean the register
-change graphic driver
-install the russian version

Does this mean TWO versions of game ?
- install game
-
-
-install the russian version

Same problem here!

My CoD has always worked fine but since yesterday it refuses to start: the tiny airplane logo flashes on the screen for a millisecond, then nothing happens.

I did nothing to its installation folder prior to the problem so I'm guessing the issue comes from somewhere else. Perhaps a 3r party application changed some files required by CoD to boot properly... who knows. I too tried to uninstall, clean the registry and reinstall the sim with no succes by the way. It's driving me nuts!

I bought the russian version and unsinstalled it when I received the french one.
I tried it again when my french version crashed but I have the same problem with it.

It's not due to patch or reinstalling the game from DVD would have solved the problem. I installed the last official patch without any problems, played with it and suddendly, it stopped working...

Like KastaRules says, it's probably due to a 3rd application, or graphic parameters, I don't know...

The fact is that we don't know what causes this and the support of 1C doesn't exist.

Thank you for your help, I hope we'll find the cause.

To be honest your problem is beyond me, but if I were you I would do this
Remove the russian version, multiple versions cant be good.
Revert your Fr Version (read forum can probably be done through steam)
clean up files and folders
allow steam to autoupdate to latest official patch (no beta)
It should be in. Program Files(x86)/steam/SteamApps/common/il-2 sturmoCoD.

I had the exact same symptoms with a poorly applied patch, yellow cross then nothing, I reinstalled the patch correctly and it worked fine, I thought this was your problem, the extra copy of the game is just a complicating factor that you dont need.

I still think one of these two things are at the root of your problem, I have had problems with this game making very minor changes, for example I changed a button mapping on my joystick and lost all joystick controls. For it to have stopped working something must have changed. If you have auto updates enabled what version is updated for example?

The russian version is already removed. I tried it to see if the problem was the same and it was.

I don't even have a yellow cross when launching the game. The launcher crashes as soon as executed, 0.00001 second after I double click.

It can't be due to patch, since I didn't install any beta patch after reinstall.

A few more details.

The error I have is a unhandledexception. The CLR20r3 :

I tried to uninstall and reinstall Framework 4.0 but it didn't work

By the way, I've installed Visual Studio 2008 recently and I think I got the problem after that...

Doesnt it seem to you that your launcher is trying to launch the wrong game version ?

Nope. Anyway, I have only one version of the game.

Same thing happened to me after I installed Visual Studio 2010 Express... long story short, ran the dotnet verfication tool (link below) and dotnet 4 failed so, un-installed Visual Studio & dotnet 4, re-installed dotnet 4, ran the dotnet verification tool (passed).

Another point worth considering is to make sure that your OS is up to date as far as service packs go etc....mine wasn't ;)

http://blogs.msdn.com/b/astebner/arc...3/8999004.aspx

Hope this helps

Goanna