Your computer’s display consists of two pieces of hardware: a video card (also known as a graphics card or display adapter), which is installed inside your computer, and the video monitor, where you see all the text and graphics your programs display. Windows uses drivers to work with these hardware devices. The majority of display problems are caused by incorrect, corrupted, or missing video drivers. Hardware failure or incorrect installation make up another set of problems, and external factors can also cause video problems.
If you have just installed Windows, or have changed your video card and are experiencing problems, the most likely cause is a missing or incorrect video driver.