An unknown directx error has occured and league of legends cannot start. please make sure your video

I went into a ranked game today ( I was playing fine ALL day , I've gotten 8 wins in a row in ranked) And now, I go into this ranked game, and my game crashes and won't start up, I go to nividia.com and update my video card (GTX 750 Ti) And go into practice tool to see that it only does this again; and i'm extremely frustrated and flustered because how the heck does it go from running fine to not being able to be played? And crashing all the time?????? I have provided a screenshot with what happened;

Here's the text for those who can't read the picture

An unknown directx error has occured and league of legends cannot start. please make sure your video card is using the latest video drivers from the manufacturer