Quite frankly, something weird seems to be going on... Could the keyboard actually be faulty? Have you, maybe, spilled some liquid into the keyboard? Does xev print anything when you press the NumLock key? What happens when you press the NumLock key while you're on the virtual console (Ctrl+Alt+F1)?
Well, at least the built-in speakers now turn off automatically when you plug in the headphones.
Well, at least the built-in speakers now turn off automatically when you plug in the headphones.