As mentioned here

http://blog.sqlauthority.com/2007/04/22/sql-server-fix-error-1418-microsoft-sql-server-the-server-network-address-can-not-be-reached-or-does-not-exist-check-the-network-address-name-and-reissue-the-command/

I followed

Step 1) system Firewall should not block SQL Server port.

Step 2) Go to Computer Management >> Service and Application >> SQL Server 2005 Configuration >> Network...