Sql server connection(Login) using server authentication.

Question

I am not able to connect to the sql server 2008 r2 using server authentication. The Password for user sa is also correct.

 ..........It gives the follwoing error.

 

Cannot connect to ABHIJIT-PC.

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A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (.Net SqlClient Data Provider)