Hi! Most modern ISPs don't require specific software or settings on the computer itself, so assuming your Belkin router is configured and ready to go, you should be able to just select its network name, enter a password if one is necessary, and connect. I believe the default network name (SSID) for Belkin routers is Belkin54g, or something similar.

However, if there does happen to be a funky wireless setup on the machine that is preventing others from being enabled, and the screenshot QEII provided does not reveal anything, follow the suggestion in this link:

http://www.ehmac.ca/mac-ipod-help-troubl...

Basically what this procedure does is delete the files related to the wireless configuration, and so after rebooting, the computer reacts as if it has never been set up on a wireless network, and it is therefore free to join another. I've seen several machines with advanced VPN options enabled that for one reason or another would not go back to default settings, and that therefore benefited from this procedure. Good luck!