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 ...

but the keyboard found in ThinkPads has the best keyboard action of any laptop around. They would make a great USB conversion keyboard, but the board to board connector is very hard to find ...