Hi, Phil,
I'd suggest that you run MJ's Help Diagnostics, choosing the
option to "Refresh Registration of all HH 1.x DLLs".
http://helpware.net/downloads/index.htm#MJs
It sounds like something has unregistered your copy of the
HTML Help ActiveX control (%windir%\system32\hhctrl.ocx).
POSTSCRIPT: This may be an issue where you first need to
unregister the HTML Help ActiveX control before you re-register it.
To do this, open a Command Prompt window and then run the following
two commands:
regsvr32 /u %windir%\system32\hhctrl.ocx
regsvr32 %windir%\system32\hhctrl.ocx
The first command unregisters the ActiveX control; the second
re-registers it.
Pete