I've followed all of the steps in http://www.gamesas.com/topic/1465357-installing-fallout-3-with-windows-78-and-xp/ to try and get Fallout 3 to stop crashing every time I press new game, but none seem to work. The only one I haven't done is to change the install path. So I just created a new folder in windows C. How do I move all the files to the new folder? And does this also have to be done with Steam for the game to work?

There are instructions available from steam on how to move the game. You would have to move the steam folder also.

Where are these instructions?

In your original post, you linked to the instructions for installing FO3. In that post is a link that will take you to the instructions.