This prompt appears when you open SQL Server:Unable to connect to ZHANGJUNJIE-PC. 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) (Microsoft SQL Server, error: 2)for help information, click: Http://go.microsoft.com/fwlink? prodname=microsoft+sql+server&evtsrc=mssqlserver&evtid=2&linkid=20476This kind of error should be the Msssqlserver service is not started so I opened SQL Server Configuration Manager ready to start msssqlserver service Click SQL Server Service discovery: Workaround: Finally find a workaround and discover The cause of the failure is: When you install Visual Studio 2012, the "Microsoft SQL Server Express LocalDB" service is installed automatically, causing the original SQL2008 to not work correctly. So here's the workaround: Open the Control Panel, locate the program----Uninstall program, uninstall Microsoft SQL Server Express LocalDB, and then open SQL Server Configuration Managerafter unloading, I found that I couldn'tSQL Server Msssqlserver service started, appearserror message:The request failed or the service did not respond in a timely manner. For more information, see the event log or other error logs. Workaround: Disable via, rebootSQL Server Msssqlserver Services Hope to be able to meet this problem of the students have helped you.