Install Outlook 2007 to replace Outlook 2002

In answering this, please assume I am technically hopeless! I have a new
Outlook 2007 to install on my laptop (with Vista) which has Outlook 2002 at
present. Is it Ok just to run it and it will overwrite the existing programme
and keep all existing files (emails, address book etc)?

I would wish to back up my existing files first but I'm not sure how to.
Unless this happens automatically, it is not currently done (which I guess is
pretty stupid). I have looked at other messages here and I can't even find
the location of the Outlook programme on my C drive as suggested in some.
Some simple instructions would be appreciated.