Wow - that was it! "ipv6 uninstall" run from the command line did it.
Interestingly enough, MS labels IPv6 on XP as "beta software". Guess it still needs work, eh?
However, I must add that 127.0.0.1 works interchangeably with localhost for me. IOW - the way it's supposed to...
Previously I had tried stopping & disabling the IPv6 service, but that did not do it. So - anyone watching this thread, please take notice that you have to actually uninstall it, not just stop & disable!
Thank you all for your responses & Happy New Year to everyone!
Best Regards,
Garret