I am working on a 2 year old Acer desktop that was never used until now. It has Windows XP Pro. I am trying to join a domain and both the Workgroup and Domain sections are greyed out. I have checked to make sure Client for Microsoft Networks is installed and checked, I have reinstalled the Nic card. It connects up fine to a workgroup but I can not change the settings to a domain or even to a different workgroup.