I CAN'T CREATE CONNECTION WITH MY DATABASE

Question

I Have got a problem with my sql server 2005 ,im doing one projet in visual studio 2005, when i am saving the datas from my form they keep one error message that"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)"
what can i do for this?