samba - Sep 2003 - Problem with windows clients accessing samba intermittently

I have a problem with samba, whereby once a day (roughly), windows
clients cannot connect to the shares, and the only cure seems to be a
reboot.
Restarting the service does not fix it, but the strange thing is, other
samba clients can connect fine ?

Anyone seen this or got any idea what the problem is ?

Thanks.

Chris Ryan