I know what a root directory is, of course, but I am finding it very difficult to explain to people what it is. I wrote a Nintendo DS application that requires a folder to be copied to the root directory of your memory card, and I often get e-mails from people who copied it to the wrong place and don't understand what the root directory is. I don't think they realize that the root directory can be thought of as a directory or "folder".
What is the best way to explain this to these people?
Maybe you could tell them to put it on the memory card itself, not in any folder.
For them, the root directory is the first folder they see when the double click the memory card icon.
You can get a lot of explanations here: http://en.wikipedia.org/wiki/Root_directory
What about using a metaphore:
You can see the folders structure as a tree. Each folder is a branch with subbranches and leaves (the files). Each branch is connected to an other (bigger branch) except one. The root.
Could you create a simple extractor/installer that will do it all for them?, could save a lot of hassle for the non-tech people.
Make them visualize it as one of those Russian dolls where the larger one holds all the remaining dolls and one by one they decrease in size.Or much like a family tree. The root directory is adam...as in adam and eve and the rest are the offspring branching outwards from Adam the highest person on the tree.