Can we use ms office 2003 and ms office 2007 together on a system?
Yes, but you need to ensure you know what you are doing. Install
MS Office 2003 first, then install Office 2007 in a different
directory. I have done this, but it was not easy and you need to
choose only ONE version of Outlook to use or both of them will not
work. Generally, it is not a good idea to use both at the same
time, but it can be done.