Vista - Vista Home Premium and wireless networking

We have more than one wireless access point (WP) in our network.
Initially, I set up Vista to use any of them, but after realizing that we
had no control over which one it uses on boot-up, I "removed" all but one
of the WPs from Vista's list of network connections. At least, I thought I
did. For some reason Vista reconnects to a "removed" WP whenever it
reboots.

* If I disconnect from "removed" WPs, Vista will not re-connect to it.

* On boot-up, it reconnects to the "removed" WP.

* When an "automatic update" is performed, Vista reconnects to the
"removed" WP.

I haven't seen anything like this since Windows ME, which I tolerated for
a whole week before scrapping it. Unfortunately, this OS has to stay on
the notebook it came with.

How can I permanently delete WPs from Vista to stop this behavior?

Any insights and/or pointers appreciated.

Neil