You have contractors or part-time personnel whose logons must be restricted to hours during which they can be supervised. You use the Hours option in User Manager for Domains to restrict the accounts to 8:00am - 5:00pm. This is a common mistake made by administrators. The Hours option sets the hours for when NT will validate the users account and allow a login. Unfortunately this setting does nothing to prevent the user from staying logged on for however long they wish. They could logon Monday morning and stay logged on until Friday. This setting does not force a logoff at 5:00pm.

To force such a logoff, select the Account Policies menu in User Manager for Domains and set the Forcibly disconnect remote user from server when logon hours expire check box.

This works to break a connection to a server but if you actually want to force a logoff of workstations at a certain time, you can use the freeware Poweroff which is a small program for Win95/98/NT/W2K to schedule a shutdown/reboot/logoff/poweroff at a certain time. It also supports command line options that allows poweroff to be used in batch scripts.