SQL connection error ( probably ) due to Internal battery changed?

Question

Hi
We have an application written in C# 2005 that use an Sql Server 2005 database with Windows authentication mode
Our customer with Windows XP sp3 used our software for a long time without any problem but he needs to change the PC internal battery and after this operation the application is not able to connect with database. I tried to uninstall all SQL server componets
and instance, and reinstall them again but it doesn't work. I think is something related to the clock time of last access to database that is in some ways influencing the connection.
What can we do?
Regards

Answer 1

I tried with your suggestion with SQLCMD - S (localhost)\TEST
Microsoft Windows XP [Sürüm 5.1.2600]
(C) Telif Hakký 1985-2001 Microsoft Corp.
C:\Documents and Settings\A>sqlcmd -S (localhost)\SILCAOEMCLIENT
HResult 0xFFFFFFFF, Level 16, State 1
SQL Network Interfaces: Error Locating Server/Instance Specified [xFFFFFFFF].
Sqlcmd: Error: Microsoft SQL Native Client : An error has occurred while establi
shing a connection to the server. When connecting to SQL Server 2005, this failu
re may be caused by the fact that under the default settings SQL Server does not
 allow remote connections..
Sqlcmd: Error: Microsoft SQL Native Client : Login timeout expired.
This is the code
server = new SQLDMO.SQLServer(); 
server.LoginSecure = true;
                // Connessione al server
server.Connect(In_sNomeIstanza, In_Utente, In_Password);
                string cs1 = "Server=(local)\\TEST;Trusted_Connection=yes";
                Sqlcon = new SqlConnection(cs1);
// THROW GENERIC EXCEPTION ????
                if (Sqlcon == null)
                    MessageBox.Show("a4", "");
                    return false;
                else
                    Sqlcon.Open();
return( true );
Thank you very much for your help!!!