Macro viruses are written in the macro language of applications such as Microsoft Word, and can potentially infect any computer that can run the application. An example is the Winword. Concept virus that infects Word 6 document files. This virus can infect Word 6 documents on any operating system. Many other applications have macro languages, so macro viruses are likely to become increasingly common.
Some people mistakenly assume that shareware, freeware, and games are the major source of viruses.
Although viruses can be easily transmitted through these sources, since they are widely copied, they have also been found in shrink-wrapped software distributed by major companies. For this reason, you should scan all software diskettes for viruses before they are used. File viruses can also be spread by downloading infected programs from the Internet. You should check software or document files transferred over a network or communications link before using them. Although the threat of losing data at the hands of a computer virus is real, the scale of the problem should be kept in perspective.