Can you get to the status page of the router? If you can does it show a connection to the cable modem? Does it show the ip subnet gateway and dns servers? A wireless network can be setup without a internet connection present. Hook back up to the pc directly from the cable modem and search the support pages for the router. Contact your isp and find out if the mac address of the connection device is stored in their record for your account. Knology in our neck of the woods requires the mac address to allow connectivity. Just a few suggestions.