It is Not a Server in general (like some people assign a computer that runs WinXP to be called a Server).
In order to be configures as a Domain the Network needs to Run with on at east one computer that is running a Server Operating System )OS), like Windows 2003, WinXP (any version) is a Client OS, it can be client (work station) to a Domain Server but can not be the Server it self.
Let say that you have a Network of 4 computers networked peer to peer all configured with WinXP Pro. You would like to upgrade the Network into a Domain network.
You have to add a new computer running Win2003, or Upgrade one of the WinXP computers to Win2003.
:sun: