Configuring a SQL Server Database for a Network Installation

By default, Remote Connections is disabled on Microsoft SQL Server 2008 R2 Express.  If a user attempts to connect to a SQL Server 2008 R2 Express database before enabling Remote Connections, one of the following error messages may appear:

A:  Cannot connect to SQL-Server-Instance-Name\SQLEXPRESS 
    Additional Information:
     An error has occurred while establishing a connection to the server. When connecting to SQL
     Server 2008, this failure may be caused by the fact that under the default settings SQL Server
     does not allow remote connections. (provider: SQL Network Interfaces, error: 28 – Server doesn’t
     support requested protocol) (Microsoft SQL Server)

B:  Cannot connect to SQL-Server-Instance-Name\SQLEXPRESS
    Additional Information:
      An error has occurred while establishing a connection to the server. When connecting to SQL
     Server 2008, this failure may be caused by the fact that under the default settings SQL Server
     does not allow remote connections. (provider: SQL Network Interfaces, error: 26 – Error Locating
     Server/Instance Specified) (Microsoft SQL Server)

C:  Cannot connect to SQL-Server-Instance-Name\SQLEXPRESS
     Additional Information:
      Login failed for user ‘username‘. (Microsoft SQL Server, Error: 18456)

This article contains instructions on how to configure Microsoft SQL Server for a network installation.