A network-related or instance-specific error occurred while establishing a connection to SQL Server.

Today, my classmates asked me why the database is open, SQL Server 2008 Management Studio opens, enter the password discovery of SA, unable to log into the database? The following error is prompted:

"A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or could not be accessed. Verify that the instance name is correct, and that SQL Server is configured to allow remote connections. (provider: Named pipe provider, ERROR:40-Unable to open connection to SQL Server) ";

He's recently installed vs 2010, and I'm guessing that the VS comes with a database that has an impact on the original standalone server.

On the internet to see others said to use the server (local) to replace the cost of localhost, but still no, and then reset the IP itself. Specific as follows:

1. Open the SQL Server Management Configurator

or enter at the command line: sqlservermanager10.msc

1. Click on the MSSQLSERVER protocol and select the TCP/IP protocol on the right side of the page

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3, right click on the TCP/IP protocol, select "Properties", you need to modify the port address of the connection database

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4, jump out of the dialog box, there are many TCP/IP ports, find "IP3", change the IP address for their own computer's IP address (or 127.0.0.1) on the TCP port to add 1433, and then select Start

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5, "IPALL" all the ports changed to "1433"

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6. Restart the service

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7, through the above 1-6 steps to set up a good port, reopen SQL Server Management Studio, the server name input: (local) or 127.0.0.1, you can log into the database.

A network-related or instance-specific error occurred while establishing a connection to SQL Server.