Netgear C3700 Modem Router Problem

I was wondering if anyone had any knowledge about how these routers work.. I bought a Netgear C3700 modem router on eBay about a month ago and couldn't get it to broadcast internet, neither wired nor wireless. When I plug it in and turn it on, all lights come on, but the internet light keeps blinking steadily even if the mac address is activated by the isp which is Comcast. I am able connect to the modem/router's interface at 192.168.0.1 and change the settings and so on. For the internet tab it says "not connected". In other words, everything looks fine but it just doesn't receive or broadcast the internet. Any idea?

Do you have the correct user and password for Comcast stored in the router?

do you mean my Comcast username and password? yes.