Do you have a Time Warner cable "Router", as you said, OR do you have a Time Warner cable "Modem"? It makes a big difference. In short, it is never a good idea to use more than one router in a given network. The DHCP circuitry in the two modems "fight" each other and cause havoc in each assigning differing IP addresses to your network's components..
Thanks for answering. I have a TWC MODEM. I know I only have one router but shouldn't I be able to see all my imac products listed
I copied and pasted my screen shots - hope this works
If you haven't already, open your Applications folder>click on "Utilities">click on "Airport Utility">there you should see an icon with your Airport Extreme showing, and there should be a Green light icon. Then click on the icon for the Airport Extreme, which will bring up a box with an "Edit" button. Click on "Edit" and there you will find the Basestation,Wireless, Network, etc. buttons. Click on each, one at a time. You should check that each of those is completed properly. Then, go back to the "Applications" folder>System Preferences>Network>here Unlock the "Padlock" icon in the lower left corner of the window by clicking on it and entering your Passwword>turn "On" the WiFi lisitng in the column of netwrks above there. Hopefully this all will resolve your issues.