problem connecting

I have 3 computers networked.XP-H, XP-Pro, & Win98SE. Internet works great
on all. XP-H & 98SE talk to each other just fine as well.
When I try to connect to either of the others with the XP-Pro PC it takes
about 3-5 minutes to connect. If I start to connect in Mynetworkplaces, then
open Mycomputer and open a second mynetworkplaces from there I can connect
and browse right away. All this time the original Mynetworkplaces still has
not connected. Eventually it will connect so I don't think its a cable or
firewall problem. After that it works quite well, for awhile. If I
disconnect and leave it for a while I need to go through the same routine
again. Internet is consistantly fast on this PC. I tried a different network
card, no difference. I even reinstalled windows, no help. I've disabled my
firewall as well, no difference.
Any ideas?
TIA