Windows 7: Primary display cut off after KVM returns

Since yesterday's Windows 7 patch, my primary display (left-side, on DVI, not connected to my single-VGA-monitor type KVM) loses signal from my Nvidia GT 240 when I switch my KVM's focus back to my Windows 7 system, and my second display (right-side, on VGA, connected to my KVM) becomes the only display (with Start button and all) as if I had disabled my left-side display. When the KVM is switched to another sytem, my left monitor gives me access to the primary Windows 7 display via a second mouse and keyboard and this still works fine - until I switch back to Windows 7. When I enter the Screen Resolution tool and click the Detect button, my dual-view configuration is instantly restored.

This problem did not occur before the latest patch install, which required a shutdown. Is this a known problem? Is there any way to prevent my primary monitor from being cut off when returning the KVM focus to my Windows 7 system?

I moved this thread to the Windows Update and Activation topics:
After update, primary display cuts off after KVM return