This might be a long shot, but since you already tried so much... have you tried disabling display scaling? There's also a compatibility setting for that. Display scaling is known to mess up a number of fullscreen games that switch to a different resolution.
I gave it a shot. I set DPI scaling to 'Application' for all the CNC3 exes, did a restart, tried again. No dice, I'm afraid
Looks like you cant turn Display scaling off completely.
(edit)
Oh, I should probably mention one thing. Shortly before this started, I did get this one huge crash.
I finished one of the Nod missions (dont remember which one) and on the results page, just before I went to save the game, my screen colors turns all corrupted and the system hangs
Everything is locked up for a minute until my PC reset itself. Dunno if its related because I tried playing again once my PC recovered and the text was still there.
The text was gone, however, the next day
