LoL Client Crashes After Pressing "Launch"

I open the League client to the launcher, press launch, hear the noise, but it never loads up to the next update window. It shows the LoLclient, LoLlauncher, and LoLpatcher as active processes, but I can go no further than that. I must reboot my computer in order to successfully log in when this happens. There are no pre-existing circumstances that I am aware of that lead to this bug.