As I have a droid phone, and Outlook 2010 doesn't work with Google Calendar Sync (according to the research I've done, it's because of MS and not Google), I'd like to use Outlook 2007.

I am running Windows 7, and purchased a copy of Office 2010 instead of 2007, which was clearly a dumb move. Now, can I downgrade Outlook to 2007 without purchasing a copy of 2007?