OK, folks...I had reverted to earlier NVIDIA drivers, to no avail. But apparently they weren't early *enough*. I re-installed version 162.67 from December 2007 and things run fine now.
Goto http://www.nvidia.com/object/winxp-2k_archive.html for the XP and Win2k legacy drivers...for the 7 series at least. If you goto the NVIDIA page for your new driver, for whatever OS, you should see a link on the left for an archive where you can get the older ones.
My thanks to Martin at Battlefront not so much for solving the problem (he didn't) but for keeping me engaged long enough to solve the problem instead of ejecting the game from my hard drive like Hephaestus from heaven.
"EAGLE THIS IS EAGLE 6, TANKS AND PCS AT TRP 3. AT MY COMMAND, TOP HAT, TOP HAT...FIRE."