Windows XP disappears from Workgroup (Net Hood) w/ Samba + WINS

[David Vincelli]

I have a funny situation where Windows XP (Home) computers appear
briefly under Network Neighbourhood (View All Computers in Workgroup
under XP) and disappear throughout the day. Win95/Win98 and Samba
boxes are always available, only Windows XP Home disappear. The boxes
are still online, and I can still access them using the \\name\share
notation (UNC). I have a feeling they are not announcing themselves on
the network as they are supposed to. How do I get them to announce
themselves. I tried making the samba server the prefered and local
master (and WINS server - dished out by DHCP) but that didn't help.
I can't figure this one out. Is there some packet I can craft and
throw on the wire to force all these computers to announce themselves?
-OR- can I modify/add a windows services on the XP boxes -OR- add a
registry key.

-- 
David Vincelli