How to Reset Airport Express
Steps: reset AirPort Express to factory default settings.
1. Unplug the AirPort express from power source.
2. Take a pen, On the AirPort express next to the audio jag see a small button named reset button. Press and hold this button with pen.
3. While holding the button down insert the AirPort Express back to its power source.
Let go of the button once the amber light flashes.