Hey guys, old user here! 
So I decided to give a shot to Fallen Enchantress: Legendary Heroes, but when I try to launch the game, I am getting the following Steam error:
Failed to start game (unknown error).
The link, which directed me to the suport site [Failed to Start the Game (Missing Executable)], advised me to "Delete the 'appcache' folder."
Done. - Same error still. after this...
1. Game reinstalled in Steam. - Same error
2. Steam reinstalled and the game is reinstalled again. - Same error.
I am on Win7 x64, but it shouldn't matter at all, this is some extremely weird error, which I never had before on Steam, and I got more games on it.
So, anyone had a problem like this? What can I do? Perhaps I should reinstall the whole OS?