I remember when my brother-in-law decided to try Office-2003. It was a complete mess. I didn't think I'd ever get it fixed. Here is the story:
Office-2003 installed over his Office-2000. His Outlook-2000 email was reformatted to the new-and-improved Outlook-2003. And Outlook-2003 format is incompatible with everything except Outlook-2003. So when his trial period was over, he could no longer access his email — unless he wanted to buy Office-2003.
Of course, I could not fully remove the "trial" version of Office-2003. Once Office-2003 has been installed, it can not overwritten with an earlier version of Office. Also, you cannot remove Office-2003 and re-install Office-2000, unless you know how to hack the registry. And you can not easily install Office-2000 and Office-2003 on the same PC.
What I eventually did to correct the situation:
- Signed up for my own trial version of Office-2003
- Used my trial version to import my brother-in-law's email file
- Saved my brother-in-law's email in another format
- Backed up his data
- Wiped his HDD
- Restored everything
In fairness, I have not used the trial version of Office-2007. But, after my experience with the trial version of Office-2003, I wouldn't touch it with a ten foot pole. Please make sure your friends don't touch it either.