Microsoft Word is a word processor program from Microsoft. It was originally written for IBM PC computers running MS-DOS. Later versions were created for the Apple Macintosh and Microsoft Windows, and became part of the Microsoft Office suite.
Word was the first popular word processor for the IBM-PC that used a graphic display mode to show typeface markups such as bold and italics directly on the screen while editing (WYSIWYG). Previous word processors such as WordStar used simple text-only display with markup codes on the screen or sometimes, at the most, alternate colors.
People should always exercise caution before they open a Microsoft Word document as they can contain computer viruses. Because of this users should have anti-virus software installed to avoid being infected by such a virus or acting as a source of infection. The first virus known to affect Microsoft Word documents was called the Comcept virus, and it first appeared on a CD that was published by Microsoft.