The first step to fix a keyboard key switch is to take off the keycap gently with a keycap puller or flat tool. Inspect the PC and wipe away any contamination with a clean air or a gentle brush. Should the switch feel wedged, try pressing it several times to make it more flexible. When dealing with mechanical keyboards, you can take out a switch and replace it with another using a switch puller and soldering tools. Press the keycap onto the stem until it snaps perfectly in place. Don’t forget to unplug your keyboard before starting work.