I now run Office 2007, including Excel 2007. But I reinstalled Excel 2003
because I need it to interface with a third party Excel 2003 based system.
When reinstalling I went to the MS Download site and successfully installed
an add-in and then tried to install the latest security update.

Everything seems to go OK but at the end I get an error message saying the
installation program could not find my version of Excel.

What to do?

Thanks for any advice