Deborah Shulman on "password being requested"

Thanks - I hadn't thought of Firefox, thats a good tip.
In the end, I re-installed, taking better note this time, of the configuration page that turns up during the 5-min WP install. The relevant username and password are set here (as distinct from the database username and password). I'm tech-challenged to put it mildly, but it does seem to have worked.