Understanding on how 3D games are working

Hello there!
I am interested gaining a deep understanding on how 3D games are working and I am looking for useful websites where I could find techniques on how to view a 3D rendered object in full detail.
I intend to learn what exactly happens in my computer when I see these visuals. You see, I am using DirectX 9.0, a graphics card with 256 megs of RAM, and a 3.0GHz CPU but I don’t have any idea how the 1s and 0s work from my hard drive to my screen. I only have a basic knowledge on how a microprocessor works so I tried searching the Internet but all I got was generic information.
For instance, I learned from www.howstuffworks.com that a computer has to render the polygons when it comes to 3D.
What I really want to understand is how DirectX works and how does it interact with the rest of the system to be able to produce 3D graphics.
I realize that what I am asking for might require for somebody with a degree to answer but I am really interested in what’s going on behind the screen I see everyday.
I am hoping you’ll be able to help me find the answers.
Thank you very much.