A network-related or instance-specific error occurred while eshtablishing a connection to SQL server.The server was not found or was not accesible.Verify that the instance name is correct and that SQL server is configured to allow remote connection .(provider:SQL Network interfaces,error:26-Error Locating Server/Instance Specified)

 i am beginner as as student..
facing problem whit add a new SQL DATAbase file in Visual studio2010 in windows8.1 single language
when ever i add sql database the windows shows me this error i try many time but :( i failed please help me to solve this problem.

my emailID is   aamerkhan4071@gmail,com
i also off my firewall but still its not working

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