Client crashes everytime a game ends.

Every time me and my girlfriend plays a game the client crashes when we press the endscreen button. My problem isnt that big, it usualy takes a around 30 sec before i get to the client, but my girlfriend's client crashes comepletely. Her screen goes all black and the coursor is loading, she cant switch to any other tabs and to get back to the client she has to open taskmanager and end LOL. It usally takes a few min to get it fixed and it happens after every game.