In a file system, there is always a folder that contains all other folders and files that is called the root. On Windows it is usually called C: while for Mac OS X and Ubuntu Linux it is / (yes.. a single bar)
Find the path of a folder
Although most of the time, softwares let you explore your files and do not ask for their path, it can happens in some more technical cases that you will need to know the path of a folder or file. Fortunately this is not rocket science, see by yourself with this example, if you have a document "magnolia.doc" that is located in the "bushes" folder which is at the root of the filesystem, its path will be /bushes/magnolia.doc (Ubuntu and Mac) C:ushesmagnolia.doc (Windows).
Find the path of a folder on Windows (soon)
It might be important to know where some elements really are in the directory tree, especially in a context where you have to recover data
from a hard drive where your softwares and files are installed.