Game Crashing after games, or if I leave computer idle for a while.

I've been having an issue with the game crashing. After every game, the client crashes and doesn't ever load up the post game screen. I can't report, honor, or chat with the players in my game. It's also irritating having to relaunch and relog after every single game I play(and I play a LOT). Additionally, my client crashes if I lock my computer for some time and come back to it, say, in a few hours. It has never done this until after patch 5.4.

Advice?