There are two possibilities here.
The first is that the XP SP2 disk is a slipstreamed copy of XP with office installed on the O/S. In this case there is no way of extracting the files as it has already been installed.
The second option is that the files are the standard install files and are launched via a script. In this case you case search the disk for all .MSI files. And dependant on the version you may have pro11.msi or std11.msi (Assuming version is 2003). If this is the case, just run the correct .MSI for your version and it will install as a standard separate disk with no effect on your O/S.