trying to run sqlcmd fails, unable to establish connection?

When I try to run sqlcmd (from the cmd prompt) I get the开发者_开发技巧 following error:

HResult 0x2, Level 16, State 1 Named Pipes Provider: Could not open a connection to SQL Server [2]. Sqlcmd: Error: Microsoft SQL Server Native Client 10.0 : A network-related or in stance-specific error has occurred while establishing a connection to SQL Server . Server is not found or not accessible. Check if instance name is correct and i f SQL Server is configured to allow remote connections. For more information see SQL Server Books Online.. Sqlcmd: Error: Microsoft SQL Server Native Client 10.0 : Login timeout expired.

Not sure why this happens? I can connect to the sql server from within my asp.net website (which runs locally, like the database) but sqlcmd can't connect.

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If you are not using the default instance, the try then following command:

sqlcmd -S MACHINENAME\INSTANCE_NAME

Notice the capital S. Also notice that I did not give it a user of password, given that default sqlcmd authentication is the windows auth, so I can log in as the current user.
For more information from Microsoft check this out > http://msdn.microsoft.com/en-us/library/ms165702.aspx

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Try sqlcmd -S <InstanceName>

• Your command will work only if you have installed the server as default instance.
• Run sp_helpserver to know the instance name.