Cannot Open SQL Server 2005 Express From C#.Net 2005 (using Code)

can anybody help me.

I am getting an sql Server 2005 connection error from c#.net 2005.

following is the error
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{"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)"}

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i have changed the default settings. local and remote connection are enabled.

following are the code i am using in C# .Net 2005
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using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;


SqlConnection conn = new SqlConnection("server=localhost; user id= sa; pwd =; Initial Catalog=testdb;");

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when i connect through the c# wizard, everything is perfect.

thanks in advance
sam alex