Power off the laptop
Unplug the charger
Remove the battery if it is removable
Ground yourself to avoid static electricity
Identify the damaged or missing key
Check whether the keycap, hinge clip, or rubber dome is damaged
Use a plastic pry tool or fingernail to gently lift the keycap
Remove the keycap carefully
Inspect the scissor mechanism or retainer clips
Reattach or replace the hinge clip if needed
Align the keycap with the retainer clips
Press the keycap down evenly until it snaps into place
Test the key for proper movement
Replace the entire key assembly if the keycap or mechanism is broken
Remove the old assembly carefully
Install the new hinge clip or keycap in the correct orientation
Press firmly until all parts lock into place
Reinstall the battery if removed
Power on the laptop
Test the key in a text editor or keyboard test tool