problem with emac and airport extreme

Hi, I just bought a second hand airport extreme card for my emac and cannot connect to my home wireless network. other phones and laptops can connect to the network with no problem. the airport icon appears in grey (no signal detected), and the network name does not appear. network diagnostics showed that no base stations were located. I had some T mobile broadband software previously installed and I think this may have screwed up my network settings or something. can anyone help? my OS is 10.4.1