Bruce, some local providers actually probhibit this without paying for wireless capability. How, I don't know. I didn't realize you can restrict the connection. My parents live down in Bristol and have Tidewater Telcom. The modem they were given only allows for a direct connection from the phone jack to the modem to the PC. Anything else in line to the PC somehow stops them from running wireless without paying extra. I think this is crazy but somehow they can stop it. I've tried with two different routers and a bunch of different software options and can't make it work. They called to find out why and were told they dont pay for the wireless service so they wouldnt be able to put any other devices in the line to the pc itself. I think they do this to combat those that dont want home phone but still want the wireless highspeed. Trying to get every bit of access they can out of people.
I'm not sure what your parents have, but there is really no way how can they limit it your connection just for one PC. If it's locked on mac address then set that mac address on your router.