Keyboard error at boot
Keyboard is not connected properly
Verify that the keyboard is connected properly to the computer by turning off your computer and then disconnecting and reconnecting the keyboard to the computer.
Ensure that there are no stuck keys on the keyboard. If all keys appear to be okay and you have a standard desktop keyboard, turn it over and gently tap the back to dislodge any dirt or hair that may be stuck.
Try another keyboard on the computer to verify that the keyboard has not gone bad.
Bad PS/2 or AT port
If all of the above solutions are not able to resolve your issue it is likely that the port (PS/2 or AT) on the back of the computer may be bad and the motherboard or I/O board may need to be replaced.