Hi Questioner,
Welcome to this Microsoft Project newsgroup
Microsoft doesn't recommend it!. However, I have all versions from Project
4 to Project 2007 on my PC without problem. But then, I only use it for
demonstration and research purposes. As far as I can tell, Microsoft is
concerned that, as each version Project produced a Global.mpt file, they may
interfere with each other. I keep mine separate by installing in different
folders. The risk is there - can you manage it?
FAQs, companion products and other useful Project information can be seen at
this web address:
http://project.mvps.org/faqs.htm
Hope this helps - please let us know how you get on
Mike Glen
MS Project MVP
See
http://tinyurl.com/2xbhc for Project Tutorials