You must find the default gateway. You can find the default gateway by typing in the run box. "cmd" this will bring up a dos prompt in that prompt type ipconfig. Get the IP address where it says DEFAULT GATEWAY
Type the number that looks like this 192.168.*.* in Internet explorer or firefox. This will bring up a web based interfaced in either firefox or internet explorer.
Example http://192.168.*.* replace the * with number from DOS box. Your router pass is default user:admin password:admin from there you can disable your wireless router and just make it a weird router. To block other devices you might want to put a Mac address filter to these computers this does get somewhat technical for a first time user.