Well, instead of calling earthlink (I just couldn't deal with them any more), I went to the website of Linksys where they have a Live Chat option. A wonderful Techie named Jocelyn F. gave me detailed instructions, which I cut and pasted to an MSWord document on my computer, on how to manually set up my wireless router. She also treated me like someone who had a problem, instead of the person who caused it. It was almost too good to be true!
Actually, it was too good to be true, at least after 3 attempts which seemed to do what they were supposed to do except that I still could not access the Internet when the signal was directed through the router. Very frustrating again. . .
BUT. . . I did find a partial solution which now has Donna back on line for her e-mail. I dug out my old Ethernet router and hooked it up. Fortunately, when I installed the wireless router some months ago, I left the Ethernet cable running between Donna's and my offices in place. It works!!!
Now only Seth has no connection from the house, nor do I from my laptop unless we find a kindly neighbor who will consent to let us go online through their signal.
At least one more small step has been taken to have us all in touch with the internet. Sigh . . . . . .