cmd31t modem needs software troubleshooting

ello, I've lost internet in my home. I called comcast the night before because the internet was being sketchy. Comcast told me the firmware on my modem was updating. Now I've lost internet all together. I called netgear and they said they need to configure the modem. She said this firmware needs to be updated and wants me to pay 80 bucks for support. Is there any way I can configure the modem myself? She said the problem as such occurs due to power outtages. So would I have to by a new modem each time a power outage or pay a fee to get the modem to work again?