If your computer is connected to a domain, Parental Controls aren't available.
You can choose which hours your children can use the computer. You can set which hours are allowed for each day of the week and block all the rest.
Watch this video to learn how to control when children can use the computer (1:30)
To control when children can use the computer
Open Parental Controls by clicking the Start button , clicking Control Panel, and then, under User Accounts and Family Safety, clicking Set up parental controls for any user.
If you're prompted for an administrator password or confirmation, type the password or provide confirmation.
Click the account that you want to set time limits for.
Under Parental Controls, click On, enforce current settings.
Click Time limits.
In the grid, click and drag the hours you want to block or allow.
For more information about using Parental Controls, see What can I control with Parental Controls? and Choose which games children can play.