Thank you Carol Haynes. That is about the information that I have come across so far.
I just find it hard to believe that there isn't a software out there to do this and thought I wasn't searching correctly (have been at it few hours now and tested a number of soft).
If I use the physical timer then all computers are shut off internet which isn't acceptable.

Yes best option, if truly no soft, is to buy a new router  :tellme:

I’m having an impossible time finding a software (Windows XP) to install on ‘my’ computer (server) to restrict ‘other’ devices (laptops, hand phones, etc) from accessing the wireless internet at X hours.
It is ‘not’ an option to install the soft on the devices that I want to block at X hours.
It must only be installed on my computer to block selected devices while other devices are still able to access the internet.
So simply unplugging the modem isn’t an option.
It could be a software that blocks X devices from any network connection (including internet) during X hours.

Also note that my router is NOT able to do as I use one supplied by ISP and this feature has been left off (confirmed). Nor am I going to use a different router.

If you know of any that meet this critea please post them, Thx! :))