I upgraded my PowerBook G4 from Tiger to Leopard yesterday. Before the upgrade Airport was working just fine. I cleared my hard drive then installed Leopard, and now any time I start a download my Airport shuts down. In order to complete a download I have to turn off Airport, turn it back on, let it work for about 5 seconds, then repeat the process until it finishes. It's obviously a problem with Airport because it does the same thing in both Safari and Firefox. Help!