Help files

Running three separate versions of NOF 4 - 7 and 9.1 .. and being 'tempted'
to buy the latest version .. the continuing problem I find is that the Help
files for each version automatically change to the latest version installed
.. thereby becoming useless for each of the older versions I am using that
do not have the updated facilities of the latest version.

How can I a) stop this and b) be able to retrieve the Help files for each
older version I want to continue to use, to edit and manage the Websites
that need to stay in that version ?

Any suggestions will be welcomed

Cheers

David