It can be very frustrating when important keys go missing from your Dell XPS L702X Keyboard. In addition, most laptop keyboard's design are different from one another, so it can be hard to find a universal manual for replacing laptop keys. Fortunately, although laptop keyboards have different designs, they have similar components. Each laptop key has three parts: a key cap and two key retainers which are two small plastic pieces that connect each key to the keyboard.
Remove your Dell XPS L702X Keyboard key retainer. The retainer consists of two small plastic pieces that attach each key to the keyboard. This will expose a small silicon membrane attached to the keyboard frame.
Use a razor blade to remove the small silicon membrane from the keyboard.
Apply some superglue to the small edge of the piece of silicon. Then place the silicon membrane back in its original position in the keyboard frame.
Re-attach the keyboard retainer piece to the keyboard frame. Attach the replacement key to the key retainer. Press down on the key until it snaps into place.