minecraft doesnt work anymore it just crashes on startup

today i was downloading another game from steam and when it finished downloading i started it up and i started it well i needed to update something so apparently i had to "roll back my video card driver"

What I expected to happen was...:
it would start up just fine like it always did i was playing it just a few moments ago untill i rolled back that driver

What actually happened was...:
it just kept crashing and every time i start it up it doesnt work so i dont know what to do anymore

Steps to Reproduce:
1. enter your minecraft Email or name
2. push play
3 when you push play and its about to open the game it says that minecraft has crashed :|