Airport Extreme not recognized iMac G5 iSight

I bought a used G5 recently and am new to the world of mac so bear with me. I've researched tons of forums trying to find an answer to this with no luck. From the start the airport card has not been recognized but the seller says it has one in it and I confirmed that model came standard with an Airport Extreme card. At one point when I did a shut down and restart it actually sort of showed up. I was able to do diagnostics through the assist me option in networks but then it just ket clocking as if it were trying to find a network but never could. Feeling a little more lucky I decided to upgrade it from the Tiger that he had installed on it to a fresh erase and install of Leopard. After plugging in to ethernet and getting all the updates now it doesn't recognize it as having an airport card installed at all again. Can anyone help me with options of what I can do to get this thing to recognize the card or do you think it's toast? Thanks!!

First, have you opened the G5 and confirmed the Airport card is there? If it is, it's possible that the card is intermittent or has completely failed. Should not be difficult at all to replace it. Here are some links which have parts for your G5:

iFixit: The free repair manual

Powerbook Medic