am i duplicating my documents if i copy them to another user account?

I had trouble with MS Office for Mac 2007 - specifically could no longer create or edit Word docs. A solution I found on the boards (when uninstall/re-install didn't work) was to create a new user account. I did this and MS Word works fine. So if I copy files from my old user account to my new user account - am i creating duplicate files taking up double the space? The solution made it clear to Copy not Move - but no explanation as to why. Can you advise? Thx.