Did you use the installer? I just uninstalled my existing LDView, then installed using LDView64-4200B1.exe, and it worked fine, without copying any files at all. I'm running on Windows 8.1, but I wouldn't have expected that to "fix" anything that might have been broken in earlier Windows, since the LDView screensaver functionality was created long before Windows 8. I did check the box during installation to install LDView as a screensaver.
Also, when you bring up the settings for the "LDView 3D LEGO Models" screensaver, does it show <LDraw Dir>\models\car.dat as the model it's supposed to display?
Also, when you bring up the settings for the "LDView 3D LEGO Models" screensaver, does it show <LDraw Dir>\models\car.dat as the model it's supposed to display?