Gee, thanks everyone for the support.
Figured it out myself. Trial and error. First, the error:
I knew that my MBP had an ATI X1600 so I went to the ATI site and downloaded the whole kit and caboodle (driver and control panel) for XP. Well, it unzipped and promptly BURPED upon install. It said that my computer didn't have any hardware compatible with any of the drivers in the download.
But in attempting to install, it erased my real Apple Boot Camp drivers and on reboot XP booted up ugly and said that it found a VGA card or some such foolishness.
So I went to our Google overlord and typed found the following:
http://ati.amd.com/support/drivers/mac/bootcamp-xp.html
Do all of this with the cover open...
1. Go there and download the driver and the control panel.
2. Install the driver first.
3. Reboot (it forces you to).
4. Set the screen to the proper settings.
5. Install the ATI control panel (the "Catalyst Control Center").
6. Reboot (it forces you to).
7. Open the control center and change the primary display to the external one (in my case, a Sceptre).
8. The MBP screen will turn off and after a click of the mouse the external screen comes on.
9. Close the cover of the MBP.
10. Have a beer.