Installing SQL Server Express 2008

Notice:

It is worth mentioning that it seems Microsoft decided, for SQLExpress installation package, not to encourage the installation of a real default SQL Server instance in favour of a defaultproposednamed instance, named, of course, SQLExpress.
If you just set to install a default instance in the Instance configuration dialog you will end up with a named instance with SQLExpress name, and not what you were looking for.
The choice could be the result of trying to help third party ISVs detecting installed SQLExpress instances on target computers, without requiring a direct call to the specific engine version description, which requires a live connection to the server.
There's a workaround to this situation, as we can provide a MSSQLSERVER instance name that will cause to install a default named instance; this definition can be simplified to a default instance :).

As usual, we can proceed repeating the already discussed steps till the Installation type dialog

where we are reported with all alredy installed engines and relative features, and we can verify

As alredy mentioned, we are going to provide the workaround name of MSSQLSERVER name to this instance in order to install a real default instance, obviously modifying the instance id name as well

We will adopt the very same collation and security account context as already used for the previous installation, and we just verify the Data Directories settings are conforming to the traditional default instances settings. As alredy mentioned, we are going to provide the workaround name of MSSQLSERVER name to this instance in order to install a real default instance, obviously modifying the instance id name as well

the check is succesfull for the Filestream setting as well

The final installation only requires a bunch of minutes to be succesfully concluded

No variation can be recorded at application level via the add remove programs applet

but we are pleased to verify the new SQL Server instance service is really available, up and running

as well as at file system level, confirming the new instance's relative presence

We can further check the current scenario connecting to both instances via SQL Server Management Studio Basic

We now only miss the configuration settings to be performed via SQL Server Configuration Manager to allow remote connections (if required) and relative TCP/IP port this instance should be listening on, as well as all other desired instance specif settings available via the facets dialog.