Cant launch the game from Steam

[Madrico]

I just bought the game but it wo'nt launch from Steam. I get the error message "Pillars Of Eternity process cannot launch, access denied, (0x5)?

 

My GeForce video drivers are up to date (Quadro K2100m).

 

I tried several things but nothing solved the issue (reinstalling steam out of the Program Files folder, reinstalling the game itself, running it as admin).

 

Do you have any clue? The game wo'nt launch as standalone neither.