Browse for Servers (Network Servers)
If you are connecting to a SQL Server component and you do not know the exact name of the SQL Server instance, click Browse for more in the Server name box to open the Browse for Servers dialog box.
This dialog is populated by the SQL Server Browser service on the server computers. There are several reasons why the name of an instance might not appear in the list:
The SQL Server Browser service might not be running on the computer running SQL Server.
UDP port 1434 might be blocked by a firewall.
The HideInstance flag might be set.
To connect to an instance that does not appear in the list, type a full connection string for the instance, including the TCP/IP port number or the named pipes pipe name.