We should look the way to prevent viruses to attack our computer because can harm our computer and cause operating system or applications program to malfunction. There is always have newly discovered viruses day by day. Thus, something need to do with our computer by installing and maintaining an anti-virus software which need some attention to make sure computer in the good health. I found this definition really informative to me on what is computer virus all about.
rogue computer program, typically a short program designed to disperse copies of itself to other computers and disrupt those computers' normal operations. A computer virus usually attaches or inserts itself to or in an executable file or the boot sector (the area that contains the first instructions executed by a computer when it is started or restarted) of a disk; those that infect both files and boot records are called bimodal viruses. Although some viruses are merely disruptive, others can destroy or corrupt data or cause an operating system or applications program to malfunction. Computer viruses are spread via floppy disks, networks, or on-line services. Several thousand computer viruses are known, and on average three to five new strains are discovered every day.
Antivirus programs and hardware have been developed to combat viruses. These search for evidence of a virus program (by checking for appearances or behavior that are characteristic of computer viruses), isolate infected files, and remove viruses from a computer's software. Researchers are working to sidestep the tedious process of manually analyzing viruses and creating protections against each by developing an automated immune system for computers patterned after biological processes. In 1995 Israel became the first country to legislate penalties both for those who write virus programs and those who spread the programs.
A distinction should be made between a virus—which must attach itself of another program to be transmitted—and a bomb, a worm, and a Trojan horse. A bomb is a program that resides silently in a computer's memory until it is triggered by a specific condition, such as a date. A worm is a destructive program that propagates itself over a network, reproducing as it goes. A Trojan horse is a malicious program that passes itself off as a benign application; it cannot reproduce itself and, like a virus, must be distributed by diskette or electronic mail.
See F. B. Cohen, A Short Course on Computer Viruses (2d ed. 1994); G. Smith, The Virus Creation Labs: A Journey into the Underground (1994); W. T. Polk et al., Anti-Virus Tools and Techniques for Computer Systems (1995); M. A. Ludwig. The Giant Black Book of Computer Viruses (2d ed. 1998); P. E. Fites, P. Johnston, and M. P. J. Kratz, The Computer Virus Crisis (1999).
source from questia.com
Hence, we can identify what cause our computer become slow, certain application malfunction, or other things that make us feel so stressful when using it. By having an anti-virus where we can get for free or purchase it, hope could be our computer's partner (not become worse). To make sure of it, we should get some advice from forumers (virus topic), do some study and read the anti-virus website thoroughly before make decision to have it. Also get some comparison among the anti-viruses to get better idea on what they are offering. Get the free one first and find it how it can help us.