I am not able to connect to a SQL server instance that running on a Windows 2003 clustered server. There is another SQL instance running on the same cluster which I can successfully access. I even attempted to access the SQL server from the physical server. When I open enterprise manager and expand the SQL server group the SQL servers displays with a green arrow indicating the SQL server services are running. However, when I click the server I need to access to expand the server's databases, DTS, management, etc, I receive the following error message: "Unable to connect to server myservername: Server: Msg 17, Level 16, State 1 [Microsoft][ODBC SQL Server Driver][DBNETLIB]SQL server does not exist or access denied." I opened the SQL server registration properties and verifed the settings. I changed the connection properties from SQL to Windows and received the same error. I verified that I am using the correct sa SQL account and password. I even added my network account to the SQL administrators group for windows authentication. I logged into the server with the server's local administrator account and received the same error message. I can stop and start the SQL server through enterprise manager. I have the same problem when I attempt to use query analyzer. I can do everything I need with the other SQL instance that is running in the same cluster.