I'm trying to install SQL Server 2005 Developer Edition on my Windows 7
(Ultimate) laptop.

When the installer gets to the 'workstation components, books online ...'
section it fails with the error :-

"Microsoft SQL Server 2005 Setup"

"A component that you have specified in the ADD_LOCAL property is
already installed. To upgrade the existing component, refer to the
template.ini and set the UPGRADE property to the name of the component."

I had Express versions of SQL Server installed from the Web Platform
installer, and compact edition versions installed from a Mobile development
workshop I did last year, but don't use.

I have just installed Visual Studio 2005 Professional, and have VS2008
Express installed also.