I have a Windows 2000 domain, configured of two Windows 2000 server (domain controllers), and Windows XP Pro and 98 client machines. Just recently I noticed that nobody can access computer within the domain The get the following error message when they click on the Domain within Network Neighborhood: "Domainname is not available. You might not have permissions to use this network resource. Contact the administrator of this server to find out if you have access permissions. The network path was not found."

Somehow sometthing changed, and I am not sure what. I have not changed any specific permssions. What could be casuing this error on everyones workstation across the network?