Arima,
It looks like this was from Steam, is that a correct assumption? Can you give more information about this crash? When you say
The Game suddenly CRASHED my computer and now it won't work anymore.
you are also referring to the game and not your computer correct?
If you could get some more information about the machine and circumstances around the crash it will help to start narrowing down a solution. In windows you can do the following:
Start->Enter "mmc" in the search box or in Win 8+ I believe you can just type mmc in the Metro view. -> File -> Add/Remove Snap-in...->Event -Viewer->Add->Local computer->Then select OK. You can then open Windows Logs->Application
If you try to run the game again and it crashes it should produce an entry here. If I could see that please.
Have you tried to uninstall and then reinstall the game? I know that might not be the most ideal solution but might be a quick fix.
If you have questions please ask I will try to help quickly,