Yes, make sure that ppt 2003 is installed before you install 2007. Don't
touch the 2003 installer while 2007 is installed.
Any other Office 2003 programs you want to run in parallel with 2007?
First, doing this is NOT recommended or supported by Microsoft.
Translated - If you have problems you are on your own. <g> Second, many
(Most) third party add ins are going to cause some problems and may even
crash either version.
With that said, I've been able to do it, after removing my add ins.