Software Time Lock

Software Time Lock is a software program for Windows 95/98/Me/2000/XP/NT /Vista computers that allows you to control at what times the Internet, specific programs, and even Windows itself can be used on a particular computer.

In addition, it can allow you to control how long these functions can be used in the course of a day.
To clarify, with Software Time Lock you can:
Set blocks of time for each day of the week during which you cannot access the Internet on a computer. For example, you can set that you cannot access the Internet Monday through Friday from midnight to 6 PM and from 10 PM to midnight. You can set several blocks for each day, such as midnight to 8 AM and 6 PM to midnight, thus creating a limited time period during which the Internet can be accessed (in this case, 8 AM to 6 PM).