The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was '*****@adelphia.net'. Subject 'Testing', Account: 'My Name', Server: 'smtp.charter.net', Protocol: SMTP, Server Response: '550 #5.1.0 Address rejected.', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79
(The email address is masked in the above message.)
Dell said it was a virus, and I went through the procedure on this forum to check. No problem was found. (All was not lost, however. I learned a lot and my computer will definitely be more secure now!)
The problem was resolved when I just happened to get Kim Komando's "Tip of the Day" today in which she talks about problems caused by the Google Toolbar for IE. I uninstalled it and instantly could send email through Outlook Express.