I upgraded from Windows 2000 to XP two weeks ago and I recently started
having this problem. It occured even though my LAN adapter is enabled and
connected.
Ipconfig shows no IP information for the LAN adapter. Ipconfig /all shows
the following information, "host name", "Primary Dns Suffix", "Node Type",
"IP Routing Enabled" and "WINS Proxy Enabled" but no IP information for the
active LAN adapter.
Ipconfig DOES, however, show the IP information for the PPP adapter when I
connect via modem.
I noticed that NetBIOS over Tcpip was disabled on the PPP adapter so I
disabled it on my LAN adapter and ipconfig now shows the IP information for
the LAN adapter. Of course turning off NetBIOS over TCP/IP makes it a bit
difficult to browse Computers Near Me in My Network Places, but there are
ways around this.