Hello jkc2255

                        In this case you can try perform hard reset on the modem and check the coax cable and the power cable on the modem connected to it firmly. Also check whether your modem is activated b your ISP ( Internet service provider) properly or not. please check for the steps mentioned on the below link to perform proper reset on the modem.

                        http://arris.force.com/consumers/articles/General_FAQs/G34-G36-Factory-Reset