I've got an Airport connected via Ethernet to a Belkin 4-port Cable/DSL Gateway Router (F5D5230-4) that assigns via DCHP. Several desktop computers, Mac and PC, are also connected to router via Ethernet, and access Internet fine. There is also a USB printer connected to the AirPort, which I have been able to print to from the Macs and PCs on the router's LAN. The problem is using the Airport not just for printing but to give wireless Internet Access to my daughter's WinXP laptop. She gets onto the Internet fine here when connected to the router via Ethernet, and at college she gets on fine wirelessly. But when trying to connect wirelessly here, we see the correct AirPort network after scanning in Network Connections (?) dialog, and we even seem to get a wireless connection, but then a valid IP address cannot be found, so of course we can't connect to the Internet. We have spent hours trying to figure out the correct combination of AirPort settings and settings on the laptop, but can't seem to get the valid IP address happening. Any suggestions?