You can ping the server. You can sign in locally using the computer name via both windows authentication and sql server authentication. Surprisingly, you can’t even sign in locally using the computer’s own IP address or localhost. Stop and restart sql server. View the application log and filter for MSSQLSERVER. Review the log entries and verify that the server is not just listening on shared memory. If it is, there’s your problem. Got the binn directory whereever sql server is installed and run SVRNETCN.exe, the Server Network Configuration Utility. Enabled TCP/IP.