Remember that computers essentially run off of a series of commands and it's usually a smooth process. But when one command conflicts with another command - or when one command asks for a process or information that isn't available, the computer returns results that aren't useable. That's an error. A prime example of this kind of error is when users attempt to use software that isn't applicable for their system. The commands in a program are pretty useless unless they have some data to act on so programmers either give the programs some data to work with (list of names or numbers for example) or they make the program generate it's own data. Sometimes, the data comes from an outside source like the Internet or the computer that the program runs on. Although WordPad is certainly no match for Microsoft Word's internal spell and grammar checker or Word's Internet linking capabilities, we believe it's a great introduction to word processing in general for computer novices. Address Book. There are hoards of advanced contact database programs floating around the Internet and on store shelves, but Windows provides a completely competent contact database of its own simply known as "Address Book. exe" /m START "c:/windows/calc.exe" /m This will run all three programs as before, however the "/m" parameter will minimize them so that they don't clutter up the desktop. Other people have found much more creative and effective ways to use batch files, but the important thing is that you know they're a resource you can use to save a few seconds or minutes in performing important tasks. jpg - This extension indicates yet another image file and it stands for "Joint Photographers Experts Group." Like the .gif file, it's commonly found on Internet web pages, however it's much smaller than both the .gif image and the .bmp image. .mid - This extension indicates a sound file created with a Musical Instrument Digital Interface. At the very end of this process, the computer looks for an operating system and if not found, it will prompt the user to tell it where it is. Earlier computers didn't have an operating system and if you have experience with the computers of the early eighties, you'll remember that most to them didn't even have a hard drive!