[Samba] Can't log on

[bear]

I am running Samba 3.02.
Mandrake Linux 10
About 20 Windows XP Home Edition Machines

I've been running Samba for a couple of years now with no problems, but 
now I am experiencing one.  One of my Windows XP Home Edition machines 
will simply not log on.  We are running plain text passwords.  We are 
not logging into a domain.  It is simply a file server.  We reformatted 
this XP machine and suddenly it asks for a username and password and 
when you enter it, it asks again...and again...and again...
I've checked that the registry entry for enableplaintextpasswords is set 
to 1.  Everything else is as it shoudl be.  Any suggestions?

jim