Aporte original por: Fred ,
You can try shutting down the computer and restart. If the keyboard came unplugged by some chance the computer will not recognize it until it has been shut down and rebooted, unless of course it is a usb keyboard. USB devices are hot swappable and do not require the computer to be off before plugging in. If that does not work you may have a bad keyboard. Luckily, they do not cost much to replace. A second hand store is a good place to pick up a spare for just such occasions.