nworkgroup lan with www connected through router/hub

Grateful for any help.
I have had a 3 X pc network for a number of years. This
nets them together and through the hub router to the web.
These pc's were all win 98se.

I have replaced one to a current standard running on win
xp home. This has required the reinstallation of the
workgroup and the router/hub. which seems to have worked
in part as follows:

pc1( win98se) links to the www and to the full workgroup
of the 3 pc's. ok

pc2 ( win98se) links to the www and the workgroup which
only consists of pc1 and itself pc2?!!!

pc3 (win xp hone) links to the www and the workgroup
which only consists of it self?!!!

Any help and advice much appreciated. Regards John