This computer's Computer Name is set to the pre-Windows NetBIOS name. The Computer Name is the first label portion of the ...

This computer's Computer Name is set to the pre-Windows NetBIOS name. The
Computer Name is the first label portion of the full DNS name of this computer.
Depending on the implementation and configuration of the DNS servers used in
your infrastructure, this DNS name might not be added to the DNS database
because the computer name contains the underscore character. Verify that the
DNS server allows host DNS names (A records owner names) to contain the
underscore character, or rename the computer so that it can be registered
in DNS. To do so, right-click My Computer, click Properties, click the Network
Identification tab, and then click Properties and modify the Computer Name.