Update :

Your path cannot contain space or special character and it should be fine. i've seen in some topics didn't mention space but it's very important to not have one

After i clicked and selected the game location with the SETUP button, the launcher still doesn't find the game and the button SETUP is still there. Even though the folder is fine and i downloaded the game 3 times. Black ops 2 and Modern Warfare 3 work fine but not World at War.