What is meant by computer program?

A dictionary might say,

"...A series of instructions or statements, in a form acceptable to a computer, prepared in order to achieve a certain result."

But that would be a boribng answer. Correct, but boring. Basically a computer program is a bunch of information you don't see that does something for you. Here's some examples of well-known computer programs.

Internet explorer iexplore.exe Windows 98 win.com Microsoft Word word.exe

You'll notice that these examples have .exe, .com at the end. This part, separated by a dot " . " is called the 'extension' of the filename. For OS's like Windows, OS2/Warp and DOS, this 3-character extension is like a license plate. It lets the computer OS, know what kind of program they are and what to do with them.

Other computer program file names are not necessarily directly used by the PC itself, but rather used to assist, store data for or record data for another program. Examples include:

mfc32.dll A library of data that other programs use. win.ini a collection of "setup" options for some versions of windows.

Files like these should not be messed with by the user. You can really foul things up.