There's no easy way to do this. It sounds like you are trying to keep people from saving data to the hard drive and possibly overcrowding it. The best way to discourage this is to allow users to create new files only in a given folder, which is wiped periodically or at logon. Another way to do this is with disk quotas, which will prevent users from saving more than a given amount to the drive.
This was first published in November 2003