After Long struggle with my server, I have found the following Issues :
That If I am on workgroup I have to use SQL Authentication. Then what I have done :
Remove the SQL server 2005 and delete all the engines before, then Install it again with enabling the Mixed authentication and defining a sa user and password.
then creating my database
configuration for remote connections , and enabling the sql browser.
then On the the TCP/Ip service double click and assgin the port , after that I found some errors in my LAN Configuration which the internet sharing is enabled, So I disable the internet sharing from the lan properties.
then I write the connection string LIke : 192.168.1.8,1433\SQLEXPRESS
then it works perfectly..
then on my software I try first to use this connection string :
string myconn = "Data Source=192.168.1.8,1433\\SQLENGINE;Initial Catalog=qn_archive;Integrated Security=True;User ID=sa;Password=password";
but it gives user is not trusted , so I remove the Integrated security fromt the string and it works fine....
Finally It works .. I appretiate your help man thanks a lot...