I usually know what I'm doing, but I've got a problem I can not seem to find a cure. First off, I have XP Pro with SP2 and all the updates. The computer in question is my mother-in-law's computer, which I built to be identical to mine. She had her network adapter stop working. When I go to "Networking Connections", it shows that it is connected, and it does detect when the cable is plugged in or not, but no IP information is shown. If I try to find the MAC address of the network interface, the information is blank.

Normal	Abnormal

This interface is built-in to the motherboard, so thinking there maybe some type of a hardware failure, I installed an additional interface via a PCI card. I again had the same type of behavior. It still detects the cable being plugged in or not. I've tried to compare the working computer to the one that doesn't gain network information and can't seem to find the difference. Any ideas? Where to look next?