SQL Server not working-- Unable to connect to Management Studio in SQL Server 2005

On Yesterday I got a call from one of my post office saying that no applications are working . It shows an error that server is not exists. Firstly I thought that it is problem with network connections and I asked them to restart the server machine and try again but then also this error exists. I came to the office and tries to run the application. But seeing the error I thought that this problem with SQL server. On trying to open the SQL server 2005 management studio I got an error. The error is as follows

“A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (.Net SqlClient Data Provider) “

First I wondered to see the error while connecting to server 2005. I never come up on such type of error during period as SA. While Contacting fellow Sys Admins they told that they had never come across such errors. While searching for the solutions on net But that not worked for me.

The main check points are

.Make sure your database engine is configured to accept remote connections
Start > All Programs > SQL Server 2005 > Configuration Tools > SQL Server Surface Area Configuration

Click on Surface Area Configuration for Services and Connections
Select the instance that is having a problem > Database Engine > Remote Connections
Enable local and remote connections

Enable the TCP/IP in surface area configuration

Check the fire wall status and off the firewall if it is on and allow exception for programs SQL server and SQL server browser

Enable SQL Server Browser (Start the SQL server browser n service)

But then also I am not able to connect to SQL server management studio. But while restarting the server machine I found that the windows server administrator password was missing. Earlier it requires a password for opening the windows server. Then I got to users (By right clicking computer---Manage----Local User) and set pass word for Administrator (Recreated the earlier Password) and restarted the server.

After this SQL Server is working and I can open management studio correctly.