How to differentiate between a file and a folder
An essential concept to understanding files and folders when working with computers is the system for organizing, storing, and locating your files in the operating system. Like in the real world where paper records are kept organized by means of a filing system, in computers, folders are used to store files that would otherwise be all over the place. An advantage to organizing files and folders in a computer is that you can create folders and subfolders to categorize and subcategorize your files for better organization.
What is a computer file?

In this context of computers a file refers to a single item such as a word document, excel document, power point document, photo, video, audio clip, etc. In simple terms, a computer file is a piece of data that is created by a computer program and can be contained by any storage media device such as a hard drive, USB memory, CD/DVD disc, or floppy disc. A computer file contains two parts, a name, and an extension. The two parts are separated by a period.

File name

The file name is the title that reveals to us the purpose of the file. It tells us what it was created for and why it’s needed. A file name can be changed at any time since changing it will not affect the file itself. You should always use descriptive names so you can recognize files at a future date and so you can better organize and categorize them in folders.
    File extension

The file extension is what tells the operating system and programs installed what type of file it is. The operating system has specific settings that can be modified for the purpose of hiding the extension of a file. This can prevent you from deleting or changing the extension accidentally. You must never alter a file’s extension (unless you know what you’re doing) as this will break the file. If this happens and you try to open the file, the operating system will not know what program to open it with.

For example, if you open a word document, it would have a file extension of .doc or .docx (for versions 2007 and 2010). If the extension was changed to something different, the file would break and thus disable the operating system’s ability to open it. If this happens, however, and you know what the extension is (in this case .doc or .docx), you can always change it back, and that should fix the problem.

What is a computer folder?

In computers, a folder has the look and feel of a “manila file folder” and they can be stored in any location of your operating system including external media storage devices. The purpose for these folders is to create a virtual filing system to organize and categorize your files. You can create, rename, and delete folders in your computer as needed. You can also create nested folders (a folder within a folder) for better organizing purposes.

For example, if you have three billing files as word documents, say, file “A”, file “B”, and file “C”, you can organize them by creating a root folder called “Billing”, and three individual subfolders called “A”, “B”, and “C” to store each of billing file in their respective folder.
Are programs kept organized within the operating system?

A program is a series of files and folders designed to perform a task. Programs including the operating system implement this structure of files and folders. Complex work and hours of intense programing are required when creating the necessary files for a computer program. These files are then stored in their respective folders according to the category they belong, so they can be organized and in one location. All programs installed in the computer are found in the root directory of the operating system.