I have intentionally put a DUN link into Windows StartUp, with Win set
not to use its Terminal Window. In the past this has worked fine and
Win did not otherwise try to connect -- or try to disconnect.

Now, my desired connect-on-startup works correctly sometimes, but
often the Terminal Window comes up -- at startup or later on --
sometimes with its enabling box unchecked and sometimes with such
checked and grayed out. If this window comes up on startup, my normal
startup gets fouled -- at least if I try canceling the undesired
Terminal Window. In that case, a 'Cancelling Connection' window comes
up and I have to Ctrl-Alt-Del twice in order to get a window that
allows me to cancel this cancelling.

How do I keep this Terminal Window from ever getting into the act?