G5 Running OS X 3.9 Won't Recognize New Network Run on Belkin N+ Router

[ragman929]

I've just bought and set up a new Belkin N+ wireless router. All 3 laptops in the house (Mac Book OS X 10.5.7, Power Book G4 OS X 10.3.9, and HP Pavilion with Vista) recognize the new network. My G5 desktop with OS X 10.3.9 doesn't. I've tried entering the name of the network and it still doesn't find it. This desktop has run for a few years off an old AirPort Base Station, which it still recognizes.

Any advice on what I can do to get it to recognize the new network?

Thanks.