Virus is the software that are made to infect the computer and also virus infects system software. Also a learner can make a virus. A virus that can destroy the whole computer system can be made using ".bat" file.
There are many types of virus like Random virus, Folder in folder virus, C destroyer virus etc...
Random virus can make lots and lots of empty or filled folders on the desktop. If a victim don't know how to stop the random virus, it may fill your complete hardisk and it may come to a crash position.
Folder into folder can make infinite folders in the folder and may harm the system if don't stop.
