A computer virus is a small software program that can spread from one computer system to another and cause interferences with computer operations. A computer virus has the capacity to corrupt or to delete data on your computer and it can use an e-mail program to spread the virus to other email addresses in your online address book. In the worst case scenario, it can even delete everything on your hard disk.
In the same way as viruses harm peoples' bodies, computer viruses can do considerable damage to computer systems. Viruses are infections. Computer infections can come in several forms and your computer can "catch" one in several ways:
Viruses in general, start working and spreading once you start using the application or program to which the virus is attached. For instance, a program that has a virus in it will place the virus in the system’s memory each time that program is run.
Once the virus is in the memory, one of several things can happen. First, it can be programmed to attach itself to other programs and applications, folders, or disks. Second, if given the chance, it can infect a network.
Computer viruses are easily spread through the use of attachments in various email messages or via messages from instant messaging; so, you must never open unexpected email attachments unless you know and trust whoever sent the message.
Be very careful as computer viruses can be easily disguised as ordinary-looking attachments or even as attractive images, funny graphics, cards, video, and audio files. Computer viruses can also spread through downloads you do while online. They can be hidden in software, especially in pirated items, or in other programs and files which you are downloading.
Viruses operate in a multitude of ways. Some will stay active only when the application to which it is attached is running. Others will be inactive once the computer is turned off, while some will run every time you turn your computer on after it has infected the network or system files.
There are some indicators that will tell you that your computer is infected:
To safeguard your files and to protect your computer, take time to understand computer viruses and what you should avoid doing to save your system from the virus. Be sure to always turn on the firewall, keep your computer’s operating system updated, update your antivirus software, and use updated antispyware programs.
See computer virus in American Heritage Dictionary 4
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