I have a machine running 11.04. Last night, everything was working fine, but this morning when I booted it, the keyboard wouldn't work. Pressing every key on it resulted in only one letter of input, and I could not get any key to consistently work.
I have tried replacing the keyboard, I've tried multiple USB ports with each keyboard, not even the on-screen virtual keyboard will work.
What's going on here and how can I fix it?
I just booted to a console and the keyboard worked fine.
Somehow, I had managed to turn on SlowKeys (Login Screen -> Universal Access Preferences).
The result was that I had to hold keys for very long periods of time for them to work. Turning it off fixed it.