My daughter wants to get Office 07 S&T edition. The 2003 edition of S&T is availible with a "free" upgrade to the 2007 S&T version. Because the 07 version does not contain Outlook, she will want to keep the 03 version of Outlook on her computer when we install the 07 upgrade version? Can this be done, or does the 07 upgrade invalidate the 03 version when installed? Her OS is Vista HP.