the ethernet port on my wife's 400 mHz TiBook isn't working. i'm running 10.3, have done all the troubleshooting i know (repair permissions, reboot, etc.), and it's still not working. when it is connected to a network, it doesn't even register anything in the network pref pane. the system profiler says it's there (en0), but it's not working. just to clarify - it's a used laptop that her school gave her...we have no prior knowledge of its working/not working... can anyone help me? is there a simple way to exchange the ethernet card in the powerbook? thanks!