Error preventing the game from loading. HELP.

I'm having problems starting a game. I have an Asus G73JW Series laptop. Every time after I choose my champion and click Start Game it doesn't go to the loading screen. An error pops up that says: "An unknown DirectX error has ocurred and League of Legends cannot start. Please make sure your video card is using the latest video drivers from the manufacturer." I just got this Asus and I'd really like to be able to play league on it. Is there anything I can do, or does anyone know how to fix that error? I'd really appreciate it