Converting Office 2007 Pro Trial to Office 2007 Small Business

My Office 2007 Professional Trial just expired yesterday. I purchased the
Office 2007 Small Business upgrade through the online store. When I tried to
convert my trial to the "real" version, my product key wouldn't work. (I
expected it to work for everything except Access, which is not included in
the Small Business version.)

I am, as we speak, downloading the Small Business version from the Microsoft
store; but do I really need to go through an uninstall/reinstall? Can't I
convert to another version of MS Office without reinstalling? I'm worried
about losing my emails & etc. from Outlook.

Help!