Error message after champion select

Everytime I finish champion select and go to the game loading screen it just goes black and i go back to my desktop and there is an error message saying:

An uknown DiretX errror has occured and League of Legands cannot start. Please make sure your video card is using the latest drivers from the manufacturer.

I have checked and all my display adaptors and grapichs processors are up to date, i am stuck with having to recconnect with the game and even after uninstalling and then reinstalling it happens again with a new game. What do i do?