[CLIENT] When I press launch on the Lol launcher it doesnt work!

Okay so I was playing League of legends one day and I closed it to play another game, soon came back and installed an update for League of legends, but then when I pressed the launch button, it closed the launcher, and the client never opens! I then searched for solutions, some work for a SINGLE launch then never works again! I've reinstalled The game lots of times to see if that works but it never does. I have also repaired the launcher, still nothing works permanently. Please fix this because I really want to play more League of Legends! Thank you for your time!