Question : Windows XP machine has "Join a domain" greyed out

I just installed a new Windows Server 2003 domain controller, the only domain controller on the network.

At the Windows XP Provessional machine, when I open My Computer Properties, under Computer Name, the option is greyed out that says "To use the Network Identification Wizard to join a domain and create a local user account, click Network ID."  Also, when I click "Change" to change the name of the computer, the "Domain" radio button is greyed out.

Help, please!  Thanks

Answer : Windows XP machine has "Join a domain" greyed out

Just to verify, this is XP Pro, not Home or MCE, right??