I'm going to have to at least touch upon the relationship between the .dlls required to install OpenGL and the .dlls required to for your video card. I'm going to explain what I 'know' and I need someone to critique me.
In order for a piece of hardware to work, a programmer must write the instructions for it to follow. These instructions are saved in libraries and installed on your computer. When you updated your video card, for example, you are updating the latest implementation for the libraries of your video card. The quality of a video device usually depends on the quality of the library that drives the hardware. In order to write your own programs that utilize your graphics hardware using OpenGL, you must install the OpenGL libraries. OpenGL acts as a specification, the OpenGL implemented on one video card should contain the same basic functionality as OpenGL implemented on another video card. Some video card manufacturers implement what are called OpenGL extensions. An OpenGL extension is functionality that lies outside the specification of the OpenGL architecture. Anyway when you write a program using OpenGL, you make calls to the OpenGL .dlls installed on your system. Those .dlls then make calls to the OpenGL enabled hardware currently installed in your system.
I think for the most part that explanation is complete, but I want to know more about the actual linking between the opengl .dlls and the video card .dlls, I don't know how they 'interface' to each other. Any questions comments, shoot.