Some problems with the client!

Lots of times when i play League of Legends and win or lose the game, the client automatically crashes and I can't honor, report or see the ending of the game score. This isn't a big problem for me, however I do have to launch Lego Legends over and over again. This doesn't occur to me always, but 50% of the time it does. The cause may be somewhere in my computer but i don't think it is very much possible.