You could always set a power on password so the kids cant even boot the PC without permission - might be a bit drastic, but thats the way it goes.
I am using 98SE withtelewest, and no matter what I do it always asks for a Networking Password, and last time I used that properly - a few years back, as unsecure as it is, if the wrong password went in, OR the cancel button was pressed, the networking features were disabled.
I am sure however if you are using 2000 or XP there is a simple way round it.