Networking XP Home & W2K Pro systems (w/ W98SE system as well)

Good afternoon, all! Please bear with me for a sec as
I've tried to research a fix for this problem for the
last 10 days, determined to fix it. Finally I see that I
need some help from YOU (and the W2K newsgroup users as
well)!

Here's the beef... Recently added an XP system to an
existing 2-computer network of a W2K Pro and a W98SE
system (connected through a Network Everywhere 4-port
router). Both old computers were able to share files and
printers on the network without issue as well as as
access the internet before we added the XP box. After we
ran XPs home network setup wizard, it made me a setup
disk to use on the W98SE system (which shares files just
fine with the XP system). However, it wouldn't work for
the W2K system at all. Long story short... Neither the XP
nor W98SE can access files or can 'see' the W2K system,
OR vice versa. However, XP & W98SE can exchange files
just fine.

Bottom line, on the W2K when I click on the workgroup
name under "My Network Places", it tells me
that "[WORKGROUP] is not accessible. The network path was
not found." That's funny, because I can ping BOTH other
computers from the W2K machine just fine, but neither
other pc can ping the W2K box (oh, and of course the XP &
W98SE can ping each other just fine). Also, Users &
passwords are identical on all 3 systems, and all 3 can
access the internet with problems.

ANY suggestions and/or resources would be GREATLY
appreciated as I am at a dead end (after apparently
stumping Pavilion support @HP with this issue).

Thanks in advance for your time, & God Bless America!