How do I restrict a User's Logon hours?
http://www.dougknox.com/xp/tips/xp_restrict_users.htm
If you are interested in forcing a logoff as well, perhaps this link will assist:
Aye Shutdown
http://www.ayesoftware.com/asd/

"RM" <RM@discussions.microsoft.com> wrote in message
news:49E8825E-A63C-4FC4-8DE2-595E83AF4B5A@microsoft.com...
>I have a friend whose teenager will not get off the computer at night. What
> would be the best way to 'schedule' the computer or internet browsing to not
> work?