Hi Mary,
I did it this way and had total success. Be aware that Outlook will always
"default" to the last version of Office you install.

Multiple versions of Office can happily co-exist in the same OS instance if
you observe the following rules:
1) Install 2003 first. At the Installation oprions, change the Program Files
Folder name from Microsoft Office to Microsoft Office 2003.
2) Then install 2007 and you can use it's default folder structure.

You probably can install both to the same Microsoft Office folder as within
that folder, i the versions are saved as Office11 and Office12 but I prefer
to do it seperately.

Usually Office (and I use Excel mostly so I'll focus on that) stores addins,
personal.xls stuff in a common folder in you Profile in documents and
settings. However, you can easily seperate the versions by looking in the
Program Files\Microsoft Office\Office12\Excel\xlstart structure to store
individual application addins, templates etc. Excel "looks" here first
before it goes to the common profile.

HTH

Regards,
Bony

"Mary" wrote:

I am having problems running certain programs made in 2003. They are not
saving properly. I have tried 'save as' 2003, tried saving as a macro
workbook, and have tried saving anyway and continuing. But they never save
correctly. If I could open them in 2003, I think it would work. I have 2007
installed and have a disk for 2003, but I am afraid to install 2003 incase it
messes up the registry or corrupts any current files I have.

Thank you for any help you can offer.