If your keyboard keys stop working, it doesn't necessarily mean they're broken or need replacement. From checking keyboard ...

By using an external keyboard, you essentially reduce the wear and tear away from your laptop's built-in keys, and that's great for keeping it looking pristine for years to come. A well-maintained ...

It may also be the driver issue. If your PC or laptop keyboard is not typing, the issue may be with your keyboard diver. If some keys are working and some are not, you need to clean your keyboard.