To install Office 97, you need to be able to read and write so many files and folders on the target computer, that normally only an Administrator can install. After installation, a user requires the following permissions:

Read and Write on these folders:

C:
C:\Temp
%SystemRoot%
%SystemRoot%\Forms
%SystemRoot%\System32
C:\Program Files\Microsoft Office
C:\Program Files\Microsoft Office\Office
C:\Program Files\Microsoft Office\Xlstart
C:\Program Files\Microsoft Office\Templates

Read and Write on these files:

C:\Ffastun.ffa
C:\Ffastun.ffl
C:\Ffastun.ffo
C:\Ffastun.ffx
%SystemRoot%\Artgalry.cag
%SystemRoot%\%UserName%.acl
%SystemRoot%\%UserName%8.xlb
%SystemRoot%\%UserName%.fav
%SystemRoot%\Mso97.acl
%SystemRoot%\Msoprefs.232
%SystemRoot%\Outlook.fav
%SystemRoot%\Outlook.prf
%SystemRoot%\Outlook.prt
%SystemRoot%\Forms\Frmcache.dat
%SystemRoot%\System32\Ffastlog.txt
%SystemRoot%\System32\Msforms.twd

You only require read access to all other folders and files that Office 97 installs,
including those that are stored in %SystemRoot% and %SystemRoot%\System32.