I found the problem
After trying everything and nearly giving up, I booted into windows and tried to play. Same "crash", except instead of being able to quit or ssh in, it just rebooted on its own!
Ended up being a fried graphics card, so I bought a new one and everything is working properly now.
I wish the problem didn't start after my huge linux update, or else I wouldn't have wasted so much time trying to look for a configuration problem. I'm gonna assume that the updates (which took 2 days of compiling) overheated the system and damaged the (cheap and generic, not overclocked) video card.
Thanks for the help,