1) Open Help and Support and type "logon hours" (without the
quotes) in the search box.
2) Go to Full text matches and click on "Net user". See the
examples for setting a user's logon hours. Some examples would be:
net user johnsw /time:M-F,08:00-17:00
net user johnsw /time:M-F,8am-5pm
net user marysl /time:M,4am-5pm;T,1pm-3pm;W-F,8:00-17:00
net user johnsw /time:all (this one means this user can
always log on)
3) Open a Command Prompt window.
4) Enter the appropriate "net user" command for the user(s) you
wish to restrict access for.
If you need to force a user to log off when their hours expire,
you may want to investigate Access Boss, from FS Pro Labs.
http://www.regnow.com/softsell/nph-softsell.cgi?item=5580-8&affiliate=52636