FAQ: fixing keyboard failure

When a keyboard doesn’t work after start-up, re-connecting the keyboard while the computer is running won’t make the keyboard work. Instead, the computer must be turned off and restarted to detect the keyboard. While the computer is off, the keyboard connector should be removed and re-inserted to confirm that it is fully connected.

The computer only checks the keyboard connection once during startup. If the connection is loose or a key gets pressed during the startup check, the computer will decide the keyboard isn’t connected and will ignore it until the next start-up.

The keyboard controller chip inside the computer uses a very slow method for checking the keyboard, around 18.2 times per second. This is slow in comparison to all of the other components that operate at millions of times per second.

To deal with this limitation, Windows doesn’t check the keyboard while running; instead, it only checks once during start-up. If Windows checked the keyboard every 10 seconds while running, there would be frequent and noticeable delays on a computer.

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