Need to locate WEP key number

if you have lost your wep key, you will have to reset your router. Before that you may want to use a wired connection to find/download an owner's manual for more specifics if you need them on belkins web-site.
After the reset you will need to setup your security again. Use a paper clip to press reset button on the back of the router. Doing this will reset your router to the way it was new out of the box. After reset shut off all devices. Then start by powering your modem, then router, then one computer with a wired connection. Go through the setup process for your router before connecting other devices.

WEP == Wired Equivalent Protocol

Connect a computer via an Ethernet-cable to the router.
Login to the router, with the correct ID/password.
Click on "wireless" and then click on "status".
The WEP-key will be displayed.