WARNING: Before proceeding, be sure to take screen shots or write down any settings you made to the modem's configuration pages as hard resetting will revert the modem to it's factory default settings. Any settings that you may have saved will be lost!
Using a paper clip, press the RESET button on the modem's back panel. While holding this button in, count to five, and then release the button.
The modem's LINK light will turn off and then it will blink slowly, about once per second. The modem has been reset to factory default.
Now you can reenter your settings.