Depends on what you want to do with the versions. I have both versions,
plus others, side by side on the computer and the main programs from both
work well. S & T can't be used for commercial purposes or charitable
purposes according to the EULA, that is why I also have other Pro versions
side by side. If you use Outlook from the 2002 version, remember that
Outlook is not included on S & T 2007.
If you don't need any of the 2002 software, you can have the 2007
installation overwrite the 2002 programs but carry the settings from the
previous version with it (and that will leave Outlook untouched.)