HOW CAN I FIX LEAGUE OF LEGENDS BLACK (PHANTOM SCREEN) ON LAUNCH

So some days before i had a little problem.... i tried to open league of legends but it couldnt open at all.. so i deleted the league.. then i understanded that i could fix it before but it was late. After downloading the game again i installed it but when i opened league to update the hole patch it was sawing me a black screen and i couldnt press anything (it was like a phantom i could see but i couldnt press nothing)