Powerbook does not detect Airport


I have a 15" Powerbook running 10.4.2. Its a 1.5GHz G4 with1Gb Ram. I put 10.4.2 on it about 3 months ago and since then it has not detected the airport. When I click "Airport Card" under "Network" in About This Mac, it says "No Information Found". Prior to installing 10.4.2 I was running the latest version of 10.3 and the airport was working fine. However, there is a bit more to the story. When I installed 10.4.2 I selected start from scratch to erase all the data and operating system on the hard drive. I wanted a clean mac. Everything else is working fine. All software updates have been done. Any ideas? Thanks.