I suspect that the new install will put MOM back but in a form suitable for the existing ATI card. It may be that your install of the new card went wrong with a weak install sscript from ATI that didn't replace the MOM utility.
Of course, I'm guessing and it all be aload of bollox. But it doesn't matter. I'd prefer you to uninstall your graphics card and drivers; switch on and do a clean install without any of the baggage being carried right now.