CM500 router and Nighthawk D700 (combo - how to disable the modem)

Hi All,

I'm a bit new to this level of network config.

Background: I have Cable and purchased a stand-alone CM500 Netgear modem and the Nighthawk D700 (modem + router). It worked prior to blowing a fuse that led me now to this point. I previously had it set up where I had wifi.

COX->CM500 Modem->D7000 Modem+router

I am currently hardwired in through the modem, however when I connect the ethernet cable to the modem/router, I cannot receive any wifi. So I am thinking that I have to (again) disable the modem on the D7000 modem+router.

First question: is that in fact what I need to do? (disable the router) And if so, how do I achieve this?

Second question: if this is NOT what I need to do, what is the appropriate action?

Thanks in advance!