hey wayjac, Thanks for the info. Its been raining in Houston and the power went out again this morning for at least an hour. When power came back on, the router connected successfully without a hitch.
I called AT&T yesterday. Their suggestion was to buy a new gateway modem. I'm not thrilled about replacing a good working modem, especially if I'm not sure that will do the trick. But I do want to get rid of the problem.