Sharepoint 2007 -Named Pipes Provider, error: 40 - Could not open a connection to sql

We took the standalone sharepoint server (SP_sql in same machine)as Virtual machine.In virtual machine there is change in the IP address and coumpter name.

After that i have run the sharepoint configuration wizard. i got error like below.

An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)

I tried below links recommended solutions but still the same error encountered.

http://www.mssqltips.com/sqlservertip/2340/resolving-could-not-open-a-connection-to-sql-server-errors/

http://www.mssqltips.com/sqlservertip/2320/understanding-sql-server-net-libraries/

Kindly help me to resolve this issue.