Open GL
 

What is GL? I run programs on my computer and they tell me that they need it to run fullscreen and still look decent. Is this something that I can download or is this because my video card isn't supporting the programs.

What is OpenGL... It's a standard: http://en.wikipedia.org/wiki/OpenGL The application complain of no implementation.

The easiest check if you have it not configured/installed would be to look to your X configuration file and see if you have Load "glx" somewhere at the beginning. The configuration details depend on your video card, but not having the line is one of the things that show you don't have it installed. Then, install Mesa.