The following components might have been installed with SQL Server Express, and need to be removed in the order listed below: Note: Uninstall of the SQL Express instances will leave behind the user-created databases, which can then be re-attached to the new instance.
Microsoft SQL Server 2005 Express CTP
Microsoft SQL Server 2005 Express Tools CTP
Microsoft SQL Server Setup Support Files
Microsoft SQL Native Client
The following components must be uninstalled last: