Did you uninstall the trial version before attempting to install
your full version? Were you signed on to Windows as
Administrator (or a user with administrator privileges), or as a
limited user? Did you get any error messages when installing the
full version? Was an older version of Office (such as Office XP,
Office 2000, Office 97, etc.) ever installed on the computer?
You should have gotten numerous reminders from Office 2003 to
activate the software before reduced functionality mode occurred,
and you apparently knew before posting your original question
that the activation wizard wouldn't start, but you conveniently
neglected to mention the latter... why, and what else didn't you
tell us? It's difficult to help when you don't give us all the
pertinent information about what you've done so far and what you
see on your screen.