Limiting internet time.

I want to limit the time my son is on the internet to two houra per day. Does anyone know of a way to set that up in Windows, or any program that might do the job? :)
Flight Simulator and other chat
https://forums.simviation.com/phpBB3/
https://forums.simviation.com/phpBB3/viewtopic.php?f=25&t=70497
Or...
...you could take my previous advice and revert back to a 56k, dial-up modem with a two hour cut-off period.... ...!
(..like us poor folks over here have to put up with).....!
I'm not sure how you would be able to limit internet time. I don't think there's a function in windows for that, atleast I couldn't find one in XP. You might have to buy some software for this
..or, the ultimate deterrent......!
Threaten to charge him for Internet time......!
Mwwhhhaaaa...!!