AE no longer gets internet connection thru cable model

This is a complicated question and I don't have all the information with me because I am between houses and stuff is scattered across two homes, two states, and itinerant people.

But....

We have a summer homein Maine that we are in the process of moving to year round. We have Time Warner (Road Runner?) for internet access. Have for years. We (I) connected an AE to it several years ago (don't have the model number with me). Everything has worked fine. Everything works fine at our soon to be former home as well.

Until now.

Our ipads, iphones, and touches all connect perfectly to the Maine AE and on through the cable modem to the Internet, as they always have. But my trusty older Macbook (running OS 10.7.5) and my wife's macbook pro (OS unknown at the moment) no longer get internet access. Diagnostics shows the laptops connecting to the AE but not though the AE to the cable modem and into the net. Restarting computers, routers, modems, etc. has done nothing. Still get the gray wireless icon with the ! in it staring at me.

Need help troubleshooting. It's worked so well for so long that my network troubleshooting skills have eroded and I am befuddled. What information should I gather? What should try first? Should I call Time Warner (please say no)?

Any ideas?

Thanks