Restrict Computer from Connecting to Outside Wireless Networks

You could just set manual IP addresses on the laptops and leave out the default gateway, then use netsh or group policy to add filters to only allow the connection to a certain wireless network and none else.

netsh wlan add filter permission=allow ssid=yournetworkssid networktype=infrastructure

netsh wlan add filter permission=denyall networktype=infrastructure

netsh wlan add filter permission=denyall networktype=adhoc

Source http://social.technet.microsoft.com/Forums/en-US/w7itpronetworking/thread/7130f1a5-70fd-429f-8d41-575085489bd1

Security through obscurity doesn't work. Never did and never will.

You could destroy WIFI card - that's the only solution which will work (and of course lock down USB, expansion slots etc!).

EDIT:

To make sure you have achieved what is required you need a cable and totally disabled WiFi network.

Remove the wifi drivers and use cables is the best solution.

If you want to keep using wifi, maybe this works? http://networking.nitecruzr.net/2005/11/make-your-wireless-computer-connect.html