Black Screen After Champ Select

So, a few days after the patch, I haven't been able to play a single game of League due to a black screen, which flickers on and off every couple of seconds, and the cursor is "loading" as if it's going to the loading screen, but never does. I can ctrl/alt/del out, but then the game crashes or I can reconnect, but the issue doesn't go away. I've noticed that if I change the resolution to windowed or borderless, the problem goes away, but I would prefer to play in fullscreen, and I would like to know why this is happening and how to fix it, especially since I've been playing in fullscreen prior to this with no problems whatsoever.

I've uninstalled League and reinstalled it. Repaired it. Turned off everything at startup. I even reset my PC to factory settings. The only "fix" I've come up with is what I mentioned above.

Any help would be greatly appreciated.