A quick walkthrough.
1. Find the default gateway address.
-Go to START > RUN > type CMD > in the black pop up window type IPCONFIG > write down the DEFAULT GATEWAY.
2. Login to the router using the Default Gateway address.
-Open your browser (Internet Explorer).
-Type the default gateway address into the browser and hit 'go'.
-It will ask you for a username and password. The default is: UN: <admin> PW: <blank>
-It is possible that this info is not the "default" anymore in which case hopefully you know it.
3. At this point you will need to look around in the configs of the router and look for a link or section that refers to the wireless. Once you find that section, look around in there for a spot that refers to the 'broadcast' or any where that sounds like it will turn the wireless off.