What is Computer Virus and Different Types of Virus

Computer viruses are small programs or scripts which are not good for your computer and nobody wishes to have them in their computers but unfortunately all of us suffer from these viruses one way or an other, virus is Invented in 1960’s , there are several types of viruses and bad peoples are inventing them every day. After the virus code is written, it is buried within an existing program, when we download any software or install it thorough disk or web, viruses runs with them and create copies of itself and infect your computer.

Definition of Virus(What is Virus)

Computer virusVirus is an infective piece of code, which has the ability to copying itself and has severe damaging effect, negative enough to ruin the health of computer, by corrupting  or destroying data, that can create files, move files, erase files, consume your computer’s memory.

Different Types of Virus

Different Types of VirusThere are many types of Virus which can bring harm to your computer, but here we will list some popular and most common viruses.

Trojan Horse

Trojan Horse is a malicious program  that pretends to have a particular function, Trojan Horse neither replicates nor copies itself, but causes damage or compromises the security of the computer, that may cause destruction to your computer. A Trojan horse is delivered by someone or hidden within another program.


Worm is a infective  program to cause slowness in a network. Made to spread through any way, it’s programmed to spread from computer to computer, it can spread by one disk drive to another or attaching itself to all your word documents or by copying itself using email or another transport mechanism, commonly spread through email attachments.


A program written to spy your actions on a computer. This program can record every key stroke and mouse click you make.  These will pop up ads, gather information and send it off to another company for market analysis, and may advertise antivirus programs and tell you your PC is unprotected, Spyware can be delivered via a Trojan horse program. spyware tracks your internet usage and sends the information back to its source.


Adware  is an annoying  program. Adware is designed to pop up advertisements on your computer . It often reports personal information back to its owner and violate privacy.

Boot Sector Virus

Boot Sector is not so common  they are nasty little programs that got loaded into your master boot record. Boot Sector Virus infects the first sector of the hard drive, where the Master Boot Record  is stored. The Master Boot Record  stores the disk’s primary partition table and to store bootstrapping instructions,  when the computer is turned on, These viruses immediately  then launch themselves before your operating system even loaded.  Today most BIOS prevents code from being written to the boot sector. Most commonly spread by floppy disks.

Time Bomb

A malicious program that is programmed to   hides on the user’s hard disk  wait for event or specific time and then after any particular action release a virus onto the computer system or network.

Browser Hijacker

Browser  Hijacker is an irritating virus,Which take control of your web browser and forcefully redirect you to other websites.

File Infector Virus

It is a virus which is found, hidden in our commonly used execution file format , like a .exe file. And get executed when we run the file.

Polymorphic Virus

Polymorphic virus is a  malicious virus, Which can replicates itself by creating multiple files of  itself, but it also changes its digital signature every time it replicates . This helps the Polymorphic Viruses to hide from anti-virus software

Macro Virus

A virus that hides itself inside of macros use another application’s macro programming language to distribute themselves. They infect documents such as MS Word or MS Excel and are typically spread to other similar documents.These macros are usually stored as part of the document or spreadsheet and can travel to other systems when these files are transferred to another computer

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Hamza Basharat

Hi. I'm Hamza Basharat, I love to find solutions and help people. I'm a senior writer at TheHelptimes and AboutEngg, and currently studying computer engineering.