9800gx2

what brand of router did u use?

As i know u can Enable/ disable the network connective during some pre-set period in the wirless router / modem router.

or some anti virus also have a function to add a parent control features to control what web page did they go to (for example if u know they use you tube a lot , then u just block the link . then they can't access it until u type a password to de-activate the parent control function.)

.......