Built-in keyboard not working on Macbook Pro

[Xiaoai]

I've been playing Brotherhood for quite a long time now, but recently when I've tried to play, the game won't respond to the Keyboard . I can still Shift+Tab into the Steam layout, but when I'm actually in-game it won't do anything. I can't get into the menu or move at all. I end up having to force quit because it absolutely refuses to respond to anything I try to do. I'm not sure what's wrong. I've tried restarting the game, and it still doesn't work. I've tried restarting my laptop, and it still doesn't work. I eventually figured I'd re-install it, and the keyboard worked initially, but the next time I tried to play the game it reverted back to being useless.

Is there anyone else who has this problem? Is there a way to fix it, or am I stuck?