Turn the power off. Look at the back of the modem and you will see a Reset or Defaults hole. Get a ball-point pen and press the button in the hole while turning the modem on. Continue to hold the button in until ALL of the lights on the modem start to flash simultaneously.
This will reset the modem back to factory defaults, and may recover your modem after you have made a mistake in changing some of the settings and don't know how to change them back.
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