Turning oplocks off, how to do?

[David J. Reiter]

Greetings All,
 Does anyone know how to turn oplocks off? I have tried everything
I can think of to disable this feature but each time the PC
will cache the file. If anybody has turned this off please send
me your configuration file. Here is the latest config file I have
tried. Thanks for any help,

David.
[global]
  printing = sysv
  printcap name = /etc/printcap
  load printers = yes
  keepalive = 60
  guest account = nobody
  username map = /opt/samba/lib/umap
  read prediction = False
  oplocks = no
  debug level = 11
  lock directory = /opt/samba/lib/locks
  kernel oplocks = no
  ole locking compatibility = no

  share modes = yes
  locking = yes
  strict locking = yes

[pc]
   path = /NEWPC
   public = yes
   only guest = yes
   writable = yes
   printable = no
   share modes = no
   oplocks = no