My game keep crashing and i can't reconnect

So, for about 2 weeks now my game keep crashing, 2- 3 time a day. It happen just after the champ select and before the loading screen. My client can't open. I can still see who is online and send a message but thats all. I just dont understand why i can't connect into game. I try multiple time to exit league and reopen it but it said your game is still in progress... I need to wait the end of the game before i can play again. I uninstall twice and it still make the same bug. Is this something that someone is aware of? Kind of tired of that bug.

ps: I'm french so my english is dusty.