Hi. After upgrading my computer and my software (from Tiger to Leopard) a strange thing happened: my Airport signal (which was the strongest before) is at the middle. But the strangest thing is that, when I open Network Preferences, my internet connection is showed as a PCI Ethernet slot 3, port 3 connection (although it shows an Airport icon); for Airport, it says it's connected but it has no IP address! I have a PCI Ethernet card, but it's not connected. I also intalled a PCI USB 2.0 card, but I don't think it has anything to do with that. Any ideas?