We aren't in Kansas anymore, Toto
John, let me take your points one at a time.
1.) I have talked to at least 3 different techs over the past week. In XP, the outgoing server was smtp.suscom-maine.net, but Win7 uses mail.suscom-maine.net for both incoming & outgoing. I am able to send myself an e-mail from the ISP's web-based Webmail; I think it it uses the same outgoing server.
2.) The port for Win7 is 587. During the marathon session with the Dell tech, we tried Safe Mode but were still unable to send.
3.) McAfee is installed on my computer. During the aforementioned marathon session, we uninstalled it & tried sending in Safe Mode with no success.
As an aside, I just pinged the server mail.suscom-maine.net & had no problems. I don't know whether that has to go through the firewall or not. Things were a heck of a lot simpler when everything was done from a green screen command line!