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Computer Viruses: Programs
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Computer viruses can not infect write protected disks or infect written documents. Viruses do not infect compressed files, unless the file was infected prior to the compression. [Compressed files are programs or files with its common characters, etc. removed to take up less space on a disk.] Viruses do not infect computer hardware, such as monitors or computer chips; they only infect software.
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How can viruses travel from an infected computer to another computer? Initially, viruses are spread by using an infected floppy. For example, an infected Microsoft Word file stored on a floppy contains a destructive or annoying program in the form of a macro or virtual basic script (tools that pre-record commands). When a human opens the file, the macro or VB script is executed by the computer, erasing files on your hard drive or inserting annoying text into the file. To counteract these kinds of viruses, software vendors build into their programs alerts that warn a person that they are opening a potentially infected file. In addition to floppies, viruses ... travel from computer to computer via email attachments.
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Computer viruses implant instructions in other programs or storage devices and can attack, scramble, or erase computer data. The danger of computer viruses lies in their ability to replicate themselves and spread from system to system. Few computing systems are immune to infection.
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Some viruses are programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Others are not designed to do any damage, but simply replicate themselves and perhaps make their presence known by presenting text, video, or audio messages. Even these benign viruses can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, many viruses are bug-ridden, and these bugs may lead to system crashes and data loss.
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Viruses are a threat to any computer that connects to the Internet. According to Wikipedia, "a computer virus is a self-replicating computer program written to alter the way a computer operates, without the permission or knowledge of the user."
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Some computer viruses damage the data on your disks by corrupting programs, deleting files, or even reformatting the disk. Just like the effects of viruses on the human body, the effects of a computer virus might not be detected for days or weeks. Some viruses are like little bombs set to cause damage at certain hours of the day or on certain dates. A virus can infect the floppy disks inserted into your computer's external disk drive. Once infected, those floppy disks can infect other computers that read the disk
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