restricted access with netgear rangemax

[kana]

I am running off xp and have computers linked ny wired connections.
I Recently bought a netgear rangemax adsl wireless router DG834PN
I was told that it can be set so that one of the PC running off it could have restricted access at certain times of the day.
There are various settings of which I have tried with the help of netgear telephone support. Chose to use telephone support as opposed to email support as it seemed quite complex several different setting screens.
So far these settings have not worked I was told to try latest firmware download but I believe that I am running off this already. If was to download this firmware would it affect my General settings ?
If anyone has a solution would appreciate it.
If not is it ok to have router switched on and off 2 times a day via a plug in mains timer adapter? I heard that you should avoid frequently turning on and off the router .Is this true?
Appreciate any help.