Why not all keys on a computer keyboard may work
Usually, when the keys on a keyboard don't work, it's due to mechanical failure. If this is the case, the keyboard needs to be replaced. However, sometimes nonfunctioning keys can be fixed. The following sections explain some methods to try and fix them.
Note: Below are the steps for troubleshooting a keyboard with some keys that work. If none of the keys are working, see our guide for keyboards that have no working keys.
If the function keys not working
If the function keys are not working, the problem may be that you have a function lock or F-lock key that needs to be toggled. The F-lock key is often found on Microsoft keyboards and pressing it activates the F-keys (F1 through F12), allowing you to use them normally.
Tip: Other keyboards may label the F-lock key as the Fn key.
If the number pad keys not working
If the keys on the Number pad do not work or are behaving oddly (for instance, if they are moving your cursor instead of typing a number), try pressing the Num Lock key. The Num Lock key activates the number keys and should type numbers when pressed.
Is the keyboard only malfunctioning in one specific program?
Make sure the key is not working in more than one application. Some keys, such as the function keys (F1 through F12), do not work with every program. An easy way to test this is to open Notepad, a word processing program, and your Internet browser, and try the key in each program.
Try Rebooting and try in Safe Mode
If you're using Microsoft Windows, try rebooting your computer and starting in Safe Mode to make sure no extra programs are running. If your keyboard works in Safe Mode, this indicates that it's one of your installed programs or device drivers causing the problem.
Try cleaning the keyboard
Dust, dirt, hair, and other debris can fall into your keyboard over time, obstructing keys or causing them to malfunction. Try removing the key that isn't working from the keyboard and clean the area under and around it.
You can also try blowing away any debris in the spaces between your keys using a can of compressed air.
If all else fails, replace the keyboard
If all of the previous suggestions have been completed and one or more keys are still not working, it is likely that the keyboard is defective and needs to be replaced.