Mercury pi865d7 vga driver

First, try to enable it. That's controllable.

The driver depends on the particular hardware, and can usually be found on your manufacturer's site if you search under Support for your model. Go here: http://www.mercury-pc.com/downloads.php , and enter your model information.
Alternatively, a very clever member here posted directions on how to identify any hardware that needs a driver. See the second post here: http://www.tomshardware.com/forum/274306-45-video-controller-compatible-driver-windows-free-download , from Saga Lout.

EDIT: Fixed broken link