How to permanently disable network access from the VM?

Hello.
For safety reasons, we would like to permanently disable network access from the VM (Windows XP).
How to disable network access definitely, and prohibit the user to simply reactivate the network connection from the VM settings available through the icons at the bottom right on the window?
It seems that even if you disable network in the configuration pane of the VM and lock it with a password, any user can pass over this setting from the Parallels Tools' icons at the bottom side of the VM windows.
Any suggestion?
Thank you for your help.