I've been trying for the last couple of days to get rid of a self-assigned IP address on my wife's white 13-inch MacBook (Model A1181, running Mac OS X 10.4.1). I've done everything from deleting files from the System Configuration folder to futzing around with keychains and changing all kinds of AirPort settings. But, as of now, still no luck - and no Internet connection. I'd really appreciate some advice and help in resolving this. Thanks for any help you can offer.