I came across a strange Windows XP networking issue today, and the magic of Google led me towards the right answer. The computer could not connect to anything on the network, and I noticed that I was not able to join it to an Active Directory domain. I saw an error message there that said “Networking is not installed or properly configured.”
I found this post describing the same issues I was experiencing: http://blog.jonschneider.com/2007/04/fix-networking-is-not-installed-or.html. Using this information, I discovered that I could just restart the “Server” service (and making sure it is set to automatic) fixed the issue. I added this comment to the page on which I found a possible solution (which worked, but was a little more complicated), and others seem to have been able to solve this problem the same way as well.
It just goes to show how useful it is to post solutions to problems online when you don’t find the exact answer right away.