If you find that the keyboard that is attached to your computer stops responding, this means that you have been "locked out" of it for whatever reason. The signals generated by the keyboard are not reaching your computer's operating system despite the fact that you are physically hitting all of the appropriate buttons. You can fix a locked out keyboard problem by first determining exactly what is causing the problem in the first place.
Make sure your keyboard is actually connected to your computer. The long wire that is attached to your computer keyboard should also be attached to a USB port on your computer's case. If this wire is unplugged, your operating system isn't going to recognize your keyboard, which will cause you to get locked out.
Restart your computer. Sometimes errors get stored in your computer's memory, and that can cause havoc on your machine. Click "Start," and then select "Shut Down" to shut down your computer. Press the "Power" button to start it back up again and see if that fixes your keyboard issues.
Click "Start." Right-click "Computer," and select "Properties." Choose "Device Manager," and scroll down to "Keyboard." Right-click on "Keyboard," and select "Properties." Click "Driver." If your keyboard is disabled, the "Enable" button will be present in this window. If the button is present, press it to enable your keyboard. This will return functionality to the device. Also, click "Roll Back Driver" to reinstall the last version of the driver for your keyboard that operated properly. This also will return functionality to the device under certain circumstances.
If that doesn't work, uninstall your keyboard from the Device Manager, and then restart your computer. Windows should detect and reinstall the keyboard when the computer boots up.