In this case we would suggest you to try the proper hard reset for one last time so  please, disconnect the coaxial cable from the back of the device? At the back of the modem, in the middle section you will see a small hole, inside that hole there is a button, and that is the reset button, please insert a paper clip or a tip of a pen and hold it for 15-30 seconds until all your lights go off, afterwards connect the coax cable back and wait until your device fully boots up. If still no lights on please reach out to Arris.com/consumersupport if your modem is under warranty.