Steve, in response to your questions/comments:

1) I only have one NIC on this machine. The adapter you identified
says it is a Nortel adapter and the only thing that I have from Nortel
is a VPN client that my wife uses with her company.

2) I could not disable the Nortel adapter so I uninstalled it and it is
now gone. "ipconfig /all" does not show anything for this adapter any
more but the problem still persists.

3) I tried resetting the tcp/ip using netsh as you suggested but it
also did not solve the problem - even after a reboot.

4) I have downloaded and installed a new driver for my NIC since this
all started so the driver is up to date and newer than the original one
I was using. Rolling back to the old driver also made no difference
(which makes sense since I was running the older driver when all this
started).

5) Even though it says I only have 1 security update, this version of
XP was absolutely current as of 2 weeks ago (when the problem started).
I have kept it updated on a fairly regular basis. I've got SP2
already loaded so maybe there is only 1 update on top of SP2...?

6) I tried a system restore before I updated the NIC driver and it said
that there were no changes in any files since several known good points
in time. I even checked all the way back to the last complete Windows
update I did and there were no changes in any of the system files. BTW
it's a real pain in the neck that the system restore reboots the
machine and then tells you there is nothing to do! That's just stupid
in my book.

7) It's getting late (past midnight) so I've got to get some sleep...
I'll read the article you posted tomorrow and try some more.

Thanks for all your help so far!