Network-related or instance-specific errors occurred while establishing a connection with SQL Server

Error message:

Title: Unable to connect to the server  
------------------------------cannot connect to  
(local).  
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Additional information: a  
network-related or instance-specific error occurred while establishing a connection with SQL Server. The server was not found or could not be accessed. Please verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named pipe provider, error:40-cannot open a connection to SQL Server) (Microsoft SQL Server, error: 2)  
For help information, click: <a target= "_blank href=" http://go.microsoft.com/fwlink? prodname=microsoft+sql+server&evtsrc=mssqlserver&evtid=2&linkid=20476 ">http://go.microsoft.com/ Fwlink? Prodname=microsoft+sql+server&evtsrc=mssqlserver&evtid=2&linkid=20476</a>  
-------------- ----------------  
button:  
determining  
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Background:

Open SQL Server 2008 SQL Server Management Studio today, enter password discovery for SA, unable to log into database, prompt information as above:

Solution:

1. Open SQL Server Management Configurator

or enter at the command line: sqlservermanager10.msc

2, click on the MSSQLSERVER protocol, the right side of the page to select the TCP/IP protocol

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