Hi George1234,
You may secure your wireless network thru your router's setting by following
this Tutorial. Please use the highest network encryption which is WPA2, make sure that you apply the same security setting to all your wireless devices in your network with the proper pass-phrase.
If for some reason, you're having a hard time connecting your wireless computers to your Belkin router, please follow
this Article on how to manually connect to your SSID (wireless network name).
An update will be nice.