Check that your DNS infrastructure is properly setup and running. All Domain
Controllers must correctly register their SRV records in DNS in order for
clients to locate them (e.g. to login). Ensure that the client's DHCP scope
has the matching DNS server IP assigned.
If this computer is a member of an Active Directory domain check it'd dns
configuration to make sure it is using ONLY AD domain controllers as it's
preferred dns servers as shown by Ipconfig/all. Also check Event Viewer
system and application logs for any helpful information and run the support
too netdiag on it which will run a battery of network connectivity, name
resolution, and domain membership tests and report results. --- Steve