My gameclient wont start
 

I have tried to start my copy of The Walking Dead several times but nothing happens, I've re-installed it, rebooted, installing and re-installing direktx for it, and even tried to buy it from a different publisher, but as it is a steam game it didnt work.
The only thing that happens is sometimes it says "This game is currently unavailable: application running"

I dont know what to do and I'm getting really annoyed