Please contact the appropriate software vendor or IT professional for assistance with this process or issue, which is beyond Blackbaud's scope of support.
During the installation of SQL 2005 Express, the "Hide Advanced Options" checkbox was not unchecked causing SQL to install to a named instance (SQLExpress) and not the default instance (MSSQLServer).
SQL 2005 Express needs to be uninstalled from Add/Remove programs on the server.

There are several components to SQL 2005 Express including:
  1. Microsoft SQL Server 2005
  2. Microsoft SQL Server 2005 Books OnLine (English)
  3. Microsoft SQL Server 2005 Native Client
  4. Microsoft SQL Server 2005 Studio Management Express
  5. MSXML Parser 6.0
Remove all components of SQL 2005 Express in the order above and reinstall SQL Server 2005 Express.