after pressing the "factory default setting", you will loose all settings you did before. make sure you have recorded all useful settings. the password of factory deault is null.

1. hardware reset

while the router is running ( act led blinking ), press the button and hold for more than 5 seconds. the act led begins to blink rapidly, then release the button. the router will restart with the factory default configuration.

2. software reset

you can also reset router to factory default via web configurator.