TCP/IP connection to host localhost via port 8080 failed. Error: "The driver received an unexpected pre-logon response. Verify the connection properties and check that the instance of SQL Server is running on the host and that this port accepts

1. Click Start-All Programs--Microsoft SQL Server2005--configuration tools-->sql Server config  manager-Select left SQL Serve R 2005 Network configuration-double-click the MSSQLSERVER protocol and select TCP/IP right click to enable;
2.  Select SQL Server 2005 on the left and select right-MSSQLSERVER-right-click to restart; wait for SQL to restart
Note: If you enable the TCP/IP network protocol, do not restart  the server SQL service will not take effect,
   Special NOTE: If the machine is not used for the server, do not open the TCP/IP services, especially the local area network, vulnerable to attack, useless when it is disabled.