In computer programming”viruses” are a type of computer program. A “virus” is a bit of code that is attached to other programs, or files. They remain hidden until activated, and can do anything from corrupting data, to sending e-mails that clog up inboxes, to completely erasing hard drives. Computer viruses go through four phases (inspired by biologists in the classification of a live virus’s life cycle).
The majority of people do not create viruses for the purposes of destruction, however. There are several reasons. One reason is bragging rights. For instance the child who folds his paper plane in a clever and innovative way to see how far the plane can fly before it comes to a stop. Some people are motivated by the same psyche like arsonists and vandals. they feel a sense of satisfaction from the destruction of property belonging to others. A powerful computer virus is like Mount Everest to some programmers, and they are driven to discover how far they can take the virus without being identified.
Certain viruses have polymorphic code which changes slightly each time they infect a file or program. This makes it more difficult for anti-virus companies to find and remove all copies of the virus from a computer. Other viruses require an “trigger” for example, an action of the user or an alarm clock, to begin spreading.
You will not achieve anything by coding a virus trojan or worm or any other malicious software as a way to get revenge and payback or pranks. It is highly likely that you’ll be convicted. Look at other options that are more enjoyable and secure than putting together malware that is malicious and could cause serious damage or even wipe your entire hard drive.