Prerequisite step: install Power Plan Assistant for Windows® 7. If it's already installed, you may, of course, skip this step.
Power Plan Assistant is required, because during its setup it adjusts the system signing policy, making it possible to install drivers
without Microsoft-approved signature (in fact, Power Plan Assistant comes with its own driver for keyboard backlight management).
Please note, this is a mandatory step! If Power Plan Assistant has not been installed, Trackpad++ driver installation will fail.