Virus

Virus

               A computer virus is a computer program that can copy itself and infect computer. The term "virus" is also commonly but enormously used to refer to other types of malware, adware, and spyware programs that do not have the reproductive ability. A true virus can only spread from one computer to another (in some form of executable code) when its host is taken to the target computer; for instance because a user sent it over a network or the Internet, or carried it on a removable medium such as a floppy disk, D, DVD, or USD drive. Viruses an increase their system or a file system that is accessed by another computer.

             The term "computer virus" is sometimes used as a catch-all phrase to include all types of malware. Malware includes computer viruses, worms, Trojans, most root kits, spyware, dishonest adware, crime-ware, and other malicious and unwanted software, including true viruses. Viruses are sometimes confused with computer worms and Trojan horses, which are technically different. A worm can exploit security vulnerabilities to spread itself to other computers without needing to be transferred as part of a host, and a Trojan horse is a program that appears harmless but has a hidden agenda. Worms and Trojans, like viruses, may cause harm to either a computer system's hosted data, functional performance, or networking throughout, when they are executed. some viruses and other malware have symptoms noticeable to the computer user, but many are surreptitious or go unnoticed.

              Computer viruses are the common cold of modern technology. they can spread swiftly across open networks such as the Internet, causing billions of rupees worth of damage  in a short span of time. Some viruses can be very destructive; they can format your hard drive, overwrite your hard drive boot sector, or delete files and render your machine inoperable.

1. Viruses enter your system via e-mail, downloads, infected floppy disks, or (occasionally) hacking.

2. By definition, a virus must be able to self-replicate (make copies of itself) to spread.

3. Thousands of viruses exist, but few are found "in the wild" (roaming, unchecked, across networks)     because most known viruses are laboratory-made, never released variations of common "wild"           viruses.

4. Virus behavior can range from annoying to destructive, but even relatively benign viruses tend to       be destructive due to bugs introduced by sloppy programming.

5. Anti-Virus software can detect nearly all types of known viruses, but it must be updated regularly to maintain effectiveness