I cannot start my client !

I put in my name and username , log in , then crashes , I get the report which says that my client crashed and if I would like to send the information to Riot Games. After that , I cannot even open the client , it crashes instantly and I receive the report . I tried restarting my PC , tried using task manager , trying running as administrator . Is this even a temporary bug? I was not able to play the game for 2 days now also I did not want to reinstall the application since it will take the whole night , any solutions to this problem would be grateful appreciated ! Thank you for reading.