Error connecting to SQL Server instance

Question

I already have SQL server 2008 R2 on my system. I also installed SQL server 2012 express. Then, I uninstalled it and installed SQL server 2012 commercial edition. I cannot connect to my DB via management studio. These weird errors happen to me all the time - 2005, 2008, 2012. The numbers change. TCP/IP is enabled, service is enabled. I just want to be able to connect and put some test databases for learning.

Please help me to fix the error below -

Cannot connect to SuperPC\\SQLEXPRESS.

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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) (Microsoft SQL Server, Error: -1)

Answer 1

Make sure that the SQL Server Service is running. Go to services from start menu, and see SQL Server, if it's not running just right click and select Start.

Answer 2

When you uninstalled SQL Express you removed the SuperPC\\SQLEXPRESS instance of SQL from your system. You will need to use a different SQL instance name. You would have set this name in the 2012 commercial version installation.

If the SQL 2008 R2 instance is the default instance on your system then the commercial SQL 2012 instance would have been installed as a named instance and you'd need to connect to it using the instance name you indicated during installation. You would connect to it using SuperPC\\[new instance name] where you replace [new instance name] with the name of the instance you set during installation.

If the SQL 2008 R2 instance is not the default instance, then the new SQL 2012 instance MAY have been installed as the default instance, in which case you just connect to it using SuperPC . It COULD still have been installed as a named instance in which case you would need to follow the directions in the above paragraph.

EDIT:
Based on your comment on your question, try connecting with SuperPC\\Sql2012 .