Client crashes in Campion Select

Since one or two Weeks my Client keeps crashing randomly, mostly in the Campion Selection. It happens in Ranked as well as in Normals (in URF too). After it crashes i have to start League of Legends again, press the Launch Button, Log in and then im in the Main Menu and it automaticly counts as and Dodge so i lose LP, have to wait 6 Minutes till i can play again and when i am in my Promos it's also counts as a Lost Game. My Pc isn't the Problem (unless my Intel i5 can't handle the League Client...).