SQL SERVER - Fix : Error : 40 - could not open a connection to SQL

Everyday I get lots of question regarding error : 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 default settings SQL server does not allow remote connection. ( provider: Named Pipes Provider, error: 40 - could not open a connection to SQL server. ) This error happens due to many reasons. There are few solutions already given on my original threads.I encourage to read following two articles first and see if you can find your solution. If you can not find any solution from here, I suggest to read additional suggestions listed below in ticket.