First download Erunt in my signature below. Run the program. This is what it is and why I'm siuggesting you do this first before you do the next steps. Failure to do so may cause problems that may include being unstable or unusable.
ERUNT (Emergency Recovery Utility NT) allows you to keep a complete backup of your registry and restore it when needed. The standard registry backup options that come with Windows back up most of the registry but not all of it. ERUNT however creates a complete backup set, including the Security hive and user related sections. ERUNT is easy to use and since it creates a full backup, there are no options or choices other than to select the location of the backup files. The backup set includes a small executable that will launch the registry restore if needed.
After you have doen the above then :
Start>Run>type in regedit>>> click enter
On the left side navigate to the following:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
On the right
You should see htmlmarq.ocx and htmlmm.ocx separate keys. Rename them to something else, ie. htmlmarq.tmp and htmlmm.tmp.
You will now be able to install Office 97, including the HTML option, without incident.
I don't know what this section of the registery does or why these files were apparently blocked (intentionally or accidently), but this solution worked flawlessly for me. If you feel uncomfortable, I'm betting you can rename the keys back to the originals and office will work, but if you need to reinstall, you'll possibly have to rename them again.