App Windows getting thrown off-screen

I figure you folks here are probably my best/quickest path to an answer on
this...

System: DELL PWS450 - Dual Screen 1280x1024 on an ATI card with ATI
Multidesk drivers.
This system has been in place and stable a long while.
About 3-4 months back I tried to update the ATI drivers, and the system went
goofy on me and I punted back to the older drivers. All was again kewl.
In the last few days, however, a new and quite annoying behavior has
appeared. When windows opens a new App window, the new window gets thrown
out into off-screen areas.
I can use the alt-space-M-<arrow keys> method of re-positioning the app
window back onto my desktop (and the ATI driver does give me a configurable
hot-key to "force all windows to screen 1"), but to say the least, this is
MOST ANNOYING and neither "solution" is entirely satisfactory.

Does anybody here know where in the registry I can look to see(/adjust)
Windows' internal
valid-desktop-coordinates-for-calculating-new-window-positions rectangle (or
even hints as to white papers or somesuch that can lead me towards a
solution)...?

Even if ATI has _even newer_ drivers, I'm a little gun-shy about trying them
at this point given my recent history with such an attempt, and - would that
really fix the problem anyway?