Symptoms
When you try to install Microsoft SQL Server 2005 Express Edition Service Pack 1 (SP1) on a computer that is running Windows Vista, you receive the following error message:

SQL Server Setup failed to execute a command for server configuration. The error was [Microsoft][SQL Native Client][SQL Server]Windows NT user or group ‘COMPUTERNAME\SQLServer2005MSSQLUser$COMPUTERNAME$MSSQLSERVER’ not found. Check the name again.. Refer to the server error logs for detailed error information.
Resolution
This problem occurs if the following conditions are true:The Windows Vista-based computer has a name thatconsists oflowercase characters or that consists of a mixture of lowercase characters and uppercase characters. For example, the computer name resembles Workstation-1.You specify a case-sensitive collation setting for the SQL Server service when you install SQL Server 2005 Express Edition SP1.Windows Vista uses the following two methods to return the computer name in response to a request for the computer name:Windows Vista can return the computer name in uppercase characters.Windows Vista can return the computer name in the actual mixed case characters that appear in the System Properties dialog box.During one part of the installation of SQL Server 2005 Express Edition, theSetup programrequests the computer name as mixed characters. However, Windows Vista returns the computer name in uppercase characters instead. The Setup program also requests the computer name in other parts of the installation of SQL Server 2005 Express Edition. Windows Vista may then return the computer name in mixed case characters.
The SQL Server 2005 Express Edition Setup program compares the received computer names. Generally, this does not cause a problem because computer names are not case sensitive in Windows Vista. However, if a case-sensitive collating sequence is specified when you install SQL Server 2005 Express Edition, the result of the name comparison between the computer name in uppercase characters and the computer name in mixed case characters fails. Therefore, the installation of SQL Server 2005 Express Edition SP1 is unsuccessful.