I know this is not the answer you are looking for:
Take a timer and set it to go on when you desire and go off two hours later.
Plug it into the wall outlet and plug your surge protector into it - the end result is that your computer will only be on for two hours a day and that will be the only time you can connect to the internet!
Sorry brocher, I just couldn't resist that! Only kidding - no offense intended!
Thinking a little more logically on the issue you could try the following:
Break the 'phone line into the computer and install a timed switch on one of the line wires.
If you were concerned about access to the switch it could be locked up or hidden.
The Maplin's electronics store next to the KFC on Great Northern Road should be able to help with any number of switches or might even know of a better solution as they have any number of telecomms gadgets in the catalogue.
Do you want to restrict it for yourself or for other users? For other users something like Cyber Sentinel 2.0, Enuff 6.0, Watchdog or this one may do it. If you want to limit it for yourself, you will have to try to forget passwords, easy if you don't want it but difficult if you want.
Not exactly sure what you are looking for.
Ep, glad to see you come back and tidy up...did want to ask a one day favor, I want to enhance my resume , was hoping you could make me administrator for a day, if so, take me right off since I won't be here to do anything, and don't know the slightest about the board, but it would be nice putting "served administrator osnn", if can do, THANKS