This is such a pain in the a--, and appreciate johnbl's solution, but I've been dealing with this Nvidia issue for years, with dual nvidia card 3-4 monitor combo's on vista and win7. It's a real problem when setting custom resolutions/timing for displays...as the settings confirmation dialog is liable to open off screen, so you have to use memorized key strokes to accept changes.
This has been going on for too many years.
My solution will involve migrating graphics hardware to ATI and operating systems to Linux. "Windows 10 will be better" is no answer at all...I loathe and detest the company that I no longer trust that put me (and my application users) in this position in the first place.