A Video Card Driver is another term for software that communicates between your Operating System and your computer hardware (e.g. the video card itself). It is important to have the most up-to-date drivers for your computer's hardware to ensure that it functions correctly.
If the video driver software for your computer is not up to date, it can cause many different graphical errors. Please click HERE for instructions on how to update your drivers through your Device Manager (instructions for Windows 10 are shown, but this should work on most versions of Windows).
If you have a standalone video/graphics card, you may want to visit the cards manufacturer's website to update your drivers.