 Occasionally, a faulty connection between a modern monitor and video card will cause the VGA part of the card to detect the monitor as monochrome; this will cause the BIOS and initial boot sequence to appear in greyscale.Usually, once the video card's drivers are loaded (for example, by continuing to boot into the operating system), they will override this detection and the monitor will return to color.The video memory of the VGA is mapped to the PC's memory via a window in the range between segments 0xA0000 and 0xBFFFF in the PC's real mode address space (A000