After a long absence out of town, I've now revisited this problem again, trying the suggestions.
When looking at and trying to adjust Display Settings, my options are only 60-75Hz, and max resolution of 1280 x 1024.....Hmmm, this is what my "desktop monitor's" specs are!
So, I have two displays -- 1.) the desktop monitor, setup 1s Display #2, but my PRIMARY DISPLAY, and 2.) My TV, 1080p, display #1. These are setup for Extended Desktop.
BUT, even though Theatre View and other things are setup to display on DISPLAY #1, it seems when I adjust Display Settings per this thread, I can only adjust for the PRIMARY DISPLAY. And I do not want my TV to be the primary display! So MC will not set the refresh / frame rate to 24p because the 19" 1280 x 1024 desktop monitor of course won't display it. If course when using CyberDVD and I use their movie mode and play to the TV, it detects and runs 24p accordingly. So everything WILL work correctly -- the problem is in MC.
Suggestions?