windows xp pro network id box greyed out

[nodular]

I have a used window xp pro machine that I have cleaned up and want to reuse at my sons school. I cannot browse my network. All computers are on the same workgroup. They can ping the xp machine and the xp machine can ping them. I have set up shares on the xp machine as well.

In the systems properties under computer name the network ID box is grey.
The guest account is on.
The windows fire wall is off. No other firewall is used. I can see the shares on the xp machine from the other machines, but cant see anything from the xp machine. Nothing shows up in my network places. When I click view workgroup computers nothing happens and I hear a ding. My network places is not shown when you press the start button. I can access the internet with out any problems. I have turned simple file sharing off and on with no difference.

Why is the Network Id box grey?
This is a XP pro box and I should be able to join domains.
Additionally when I run the network setup wizard should the first question be about joining a domain or not?
I have played with this thing and scoured the forums and internet for an answer.

Help me obi wan your my only hope!

[ProfessorU]

You may need to be logged in as the local administrator to change the Network ID.

I would guess corrupt files on your XP machine, since it's obviously on the network. Since you can't just reinstall the networking components, I would try to overinstall after booting from the XP CD.