Critical Error

I was in a game and had an error, which said it needed to close League, and it locks me out from even using Windows tab viewer or task manager to close it. I sign out and sign back in and try to reconnect and have the same critical error message.

I have done a full reinstall, repair, and turned off my internet security tools. Nothing has worked I still get the same message when I load into the game after the lobby.

What do I do to solve this issue?