A virus is a program or piece of code which are made with malicious intention. It has the ability to replicate itself, create, move or erase files. Some computer virus can travel through networks. An antivirus can safeguard your computer from virus infections.
Types of computer viruses
Boot sector virus
This type of virus is also known as master boot record virus. This virus attacks the boot sector of the hard disc and remains hidden until it is accessed.
A Directory virus or file system virus infects a file by changing the path which shows the location of that file.
Memory resident virus
They get settled in the computer memory and get life whenever the OS runs. These viruses hide in the RAM.
This virus deletes the information stored in a file which it affects. However, the size of the file is unchanged.
Direct action virus
As the name indicates, these viruses work only when file attacked by this virus is opened.
They infect files with macros, templates etc that are contained in a file. They hide in E-mail and networks.