[CRASH][CLIENT] An unknown directx error has occurred, can't launch or log in

I queued up for a game in teambuilder, and the matchmaking proceeds as normal. When the loading screen launches, it crashes and says "An unknown directx error has occurred" and tells me to check my drivers. The client is still open in the background and doesn't give me the option to reconnect, so I have to relog. I had this problem twice in a row yesterday (in the same game) and it fixed itself. I was only a minute or two late for an ARAM, so I didn't worry about it. This time, however, it was on summoner's rift, and I relogged 12 times (which took a while because the login server was taking multiple attempts to receive a response) before restarting my computer. After I had restarted, it took well over 100 tries to launch the client (I would click on it in my taskbar, it would highlight and appear to launch, then fade away without doing anything. It appeared in my processes in task manager, but never in the applications list), and when it finally launched, and took 2-3 minutes to log in, I discover that my team had surrendered at 20 minutes and I never connected to the game.

I'm on a state-of-the-art engineering laptop on a wired gigabit connection. No other applications interfered with the client.

Given the history of similar problems I've had, it's very likely that this is "riot-side."

Hopefully no negative repercussions will come from "leaving" this match, since I had to click "Yes I want to leave" to try to reconnect to the game, and I moved mountains in order to try to reconnect to the game, only to have it spit in my face.

In the meantime, I will play ARAMs because the problem seems to be inconsistent.