On Windows 8.1, no matter the client I have downloaded the game. I will start the game and view the log in screen, it only takes a second or two before the entire screen goes black. The music still plays and I assume the gameplay actually works but I simply can't see anything. If I go and click on firefox or anything else with the game still up - the screen becomes visible again. That is until I click on the game, where it goes black yet again.