There are a lot of reasons why users may opt to use a USB keyboard instead of the built-in laptop keyboard. I, for one, accidentally spilled a cup of water to my friend’s laptop and the liquid seeped through the keyboard circuitry. Fortunately only the keyboard was damaged (although I’m pretty sure my friend was angry at me) and the other parts of the laptop’s motherboard remain untouched.
Nonetheless, the water had shorted the keyboard circuit which resulted to some keys as always pressed even when they were not touched. This caused problems when typing passwords or just about any computer activity that requires the keyboard. The next most logical thing I thought to consulting a computer technician (which my friend is either lazy or stubborn to do so) was to disable the laptop keyboard.
Disabling the laptop keyboard can be done by opening the laptop and unplugging the keyboard from the motherboard. Another easier method is to replace the current keyboard driver with an incompatible driver.
Using an Incompatible Driver
When tinkering with the keyboard’s driver, the only solution is to use a driver that is not compatible, say a driver for Japanese keyboards used on an American QWERTY keyboard.
To do this, (note: tested on Windows 7 only)
Click the Start button.
Type Device Manager in the search box.
Click Device Manager in the list of results.
With the Device Manager opened,
Click Keyboards in the list of devices to expand it.
Right-click Standard PS/2 Keyboard.
The Standard PS/2 Keyboard Properties dialog box will appear. Click Update Driver in the Driver tab.
In the next dialog box, select Browse my computer for driver software.
Select Let me pick from a list of device drivers on my computer.
Uncheck Show compatible hardware.
Select an incompatible driver and click Next.
When the new driver software has been installed, click Close.
Uninstalling the driver is fruitless since during restart the computer will detect the keyboard hardware, search for the right driver, and reinstall it. You cannot also disable the keyboard since the Disable button is itself disabled.
Unplugging the Keyboard Ribbon
If you would like to physically disable the keyboard, you can do so by unplugging the ribbon connector of the laptop keyboard. This requires removing the hinge cover, some unscrewing here and there, and lifting the keyboard to reveal the connector.
This method is also ideal when you have a keyboard replacement.
Like I said before, the best step is to just let a technician solve the problem for you, especially when you are not familiar with computer troubleshooting.