This worked for me on my 4830 card - anyway, I read further on the forums, one poster suggested using ALT+TAB to go out to the desktop and then back in by ALT+TAB, and the text problem was fixed.
Well, I tried that, and it works fine now. I can again see all the text in the scenario and mission boxes, and in-game boxes. Hmmm. I apparently need to do this at the start-up of each game. Also worked fine in CMBB - whew!
Thanks for all the help, I would have never tried this on my own...