ya thanks a lot. Actually my problem is solved when we are connecting to the server in ServerName we have to write computer nameDBSERVER and then Studio Express gets connected.
Are you trying to connect remotely ?
A few things to check:
-Make sure you are using the correct server and instance names.
-In Configuration Manager, make sure that SQL Server and SQL Server browser are running
-In Configuration Manager, make sure TCP/IP is enabled
-Make sure remote connections are enabled (if needed)
-Make sure no firewall is blocking access to the SQL Server port.