Well, here's what went on. All browsers used the broadband connection as expected, while all my mail clients (T-bird, Mozilla mail, even LookOut Express) all insisted on dialing out. The clients all (in their own incompatible ways) were telling me that they thought they were using the LAn connection. However, the modem tones belied that.
I even got rid of the dialup connection definition, and tried making connections. That was less than helpful; T-bird kept insisting that there was an error wth the POP3 server, and that the server was responding with nothing (which I translated to: There's no connection with the server right now...).
After much beating head against wall, I noticed that the AVG E-mail scanner was always active as soon as a connection to any email server was activated. Hmmm...is there something there that might give a clue? So I went to the screen for the e-mail scanner. Nothing particularly usefull in either the plug-in or general tabs. OK, so lets start "pushing all the buttons as fast as you can" (the standard way of programming a microwave, in case you're wondering...) and see what's under the blankets.
"Configure". Seems reasonable...Uhhhh, well, all this does is to determine whether scanning is done on incoming and/or outgoing mail, and whether AVG will drop a small blurb that it has scanned the mail. Noting to see here...move along....
"Properties". OK, whatwegothere? Message queue directory...Network connection...Hmmm... Set to Dialup?!? What the hey...OK, click the Edit button, and we have a nice modal dialog that has two radio-buttons available: "Dialup" and "LAN". Sheesh! So the dialog hidden some 3 or 4 levels deep overrides the entire set of system settings and forces a dial-up mail connection regardless of how the rest of your system is configured?!? What a complete crock of shit! Any reasonable program will wait for the connection to be made, and use what the mail client tells it to use and filter the input stream. Note that the shitferbrains dialog doesn't have a "use what the system says, you fucking dumbshit" setting.
<angry grumble!>
So after three days of fucking around with this, It's now fixed. The only thing left to figure out is how to get my domain forwarded to the new ISP (remember, Comcast does not host domains, in spite of what their sales drones will tell you!)
We're almost there, folks....
In the imortal words of Cheryl Crow:
Nobody said it would be easy
but nobody said it would be this hard....