Rajiv Singha
A free guide to 7 computer viruses you should know about
March 13, 2018


Computer viruses are nasty little programs that are designed to lay waste to your computer. Some destroy files stored on your PC, while some trigger different software to malfunction. More nefarious viruses steal your confidential information and some even go to an extent to rig a system’s power load and cause it to catch fire. Some nasty little things these viruses are! So, the more you know about viruses and how they work, the more prepared you will find yourself when they come knocking. And with that thought, here are 7 computer viruses you should know about.

1. Polymorphic Virus

‘Nasty’ is underrated when we talk about this virus family. When a polymorphic virus infects a computer, before it starts multiplying it creates copies of itself with every copy slightly different from one another. And because this virus is capable of creating such duplicates constantly, it can be difficult for antivirus programs to detect it.

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2. Resident Virus

A resident virus is different from a non-resident virus in the way it functions. A non-resident virus needs to be executed first, before it begins its infection. However, a resident virus can activate itself whenever the operating system loads. It is able to do this because it stores and hides within the memory of the infected computer, which is why it is difficult to get rid of such viruses.

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3. Boot Sector Virus

First, let’s understand what is a boot sector – it is a section on a computer’s hard drive or an external storage media. This section contains information which is required to boot a computer. A boot sector virus infects part of this boot sector called the master boot record (MBR) and replaces legitimate information with its own infected version. The virus gets activated before the operating system loads and it may make the infected computer unbootable.

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4. Multipartite Virus

While other viruses attack one component of a computer at a time, a multipartite virus attacks two. This virus can infect both the boot sector and the system or program files at the same time. This triggers infections at multiple sections in the computer – just like multiple bombs detonating at various places at the same time. Because of this dual infection approach, the multipartite virus can re-infect the same system over and over again until all its components are completely eradicated.

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5. Overwriting Virus

True to its name, an overwriting virus destroys the file it infects. It does this by overwriting data in the system’s memory. The virus can be removed only by deleting the infected file. Often, cleaning an overwriting virus means losing the infected programs and reinstalling them.

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6. Browser Hijacker Virus

It’s also known as a browser redirect virus and so because it’s sole purpose is to redirect you to websites without your consent. Once inside a computer, it modifies the settings of the web browser (including default search engine and home page) and takes a user to malicious websites (in most cases). A browser hijacker spreads through malicious email attachments, free downloads or when a user visits an infected website. This virus can install a spyware on the infected system and this may compromise the user’s private data (personal or financial information). It can also install other viruses such as ransomware that encrypts a system’s data and demands money (ransom) in exchange.


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7. Macro Virus

Let’s first understand what is macro. Macro is a set of commands that can be installed in programs like MS Word or Excel to trigger a specific function automatically. It is mostly used for automating common, repetitive tasks. A macro virus is a malicious program that is written in the same macro language and replaces/alters a pre-installed macro in a program like MS Word or Excel. And when such a document is opened, it causes a series of actions to begin automatically. These actions include infecting every other document on a user’s computer, causing irregularities in text documents, accessing email accounts, sending spam messages to people in the user’s address books, etc. A macro virus can affect Windows, Linux and even Mac.

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What we have described here about these 5 computer viruses is just one tiny aspect of what they do. Details on how viruses and malware function might not be easily comprehended by everyday users. But the main message here is that such malicious programs can turn your digital devices against you. And the only way you can defeat them is by educating yourself on cybersecurity and using a multilayered security solution that can stand between these threats and your computer.


If you think is post is helpful and information, do share it with your friends and peers.




This post has been updated as of 13.3.2017


Malware, viruses

Have something to add to this story? Share it in the comments.

Rajiv Singha
About Rajiv Singha
Rajiv is an IT security news junkie and a computer security blogger at Quick Heal. He is passionate about promoting cybersecurity awareness, content and digital...
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  1. SUJIT KUMAR JANAJanuary 24, 2017 at 5:19 PM


  2. KISHOR KUMAR DASJanuary 24, 2017 at 8:11 PM

    Lot of thanks for this message.

  3. Kriyanta HaldarJanuary 25, 2017 at 12:06 AM

    But..How to get rid of these Virus, and do formatting the PC solves the problem..??

  4. It is very educative to the PC users but the point is how to deal with such uninvited threats. One is buy and install good antivirus what are the others do’s and do not do’s.

  5. Thank you for your kind information

  6. rangeswaranJanuary 25, 2017 at 7:57 AM


  7. ARVIND KOLIJanuary 25, 2017 at 7:58 AM

    १० यूजर कि
    क्विक हेअल टोटल सिक्यूरिटी उपडेट नहीं हो रहा है
    रजिस्टर होने के बाद उपडेट होके उपडेट छोड़ देता है और COPY IS NOT REGISTERED बताता है क्या करे

  8. gsjana2014@gmail.comJanuary 25, 2017 at 8:24 AM

    Gouri Sankar Jana : January 25,2017 at 8:22AM
    This is a Surprise message.

  9. zamzam towerJanuary 25, 2017 at 10:28 AM

    5 dangerous computer virus every PC. pls solution this my computer virus

  10. akdhupar@gmail.comJanuary 25, 2017 at 12:13 PM


  11. Nice customers services

  12. AJAY PRATAPJanuary 25, 2017 at 2:26 PM

    Dear Rajib, Way to go!

  13. krishna sharmaJanuary 25, 2017 at 6:43 PM

    thanks for the alert ,please help me

  14. yuvraj mishraJanuary 25, 2017 at 7:05 PM

    how to destroyed the this virus

  15. Nice services

  16. Naresh PareyaJanuary 26, 2017 at 12:13 AM

    Is free downloading effect my system?

  17. rezabipara.jpt@gmail.comJanuary 26, 2017 at 5:14 AM

    How to I am virus protected my computer

  18. Kar AshamukulJanuary 26, 2017 at 5:36 AM

    26.01.2017My computer is affected from the last evening producing multiple files of the same name. I use Quick Total Security to protect my computer. Pl help.
    Kar Ashamukul 26.01.2017
    mail address:

  19. my computer have 5 virus

  20. thanks man! but i still have a pinch of doubt that can my Gaurdian NetSecure(Quick Heal Group) eradicate these virus! If yes then just By simple system scan??

    and By the way thank you @Rajib Singha!!!!!!!

  21. syed abdur rahmanJanuary 26, 2017 at 4:09 PM

    I have read the article but a Person Like Us who dont know how to get the system free from such viruses what sort of remedy you suggest to get rid of it, Kindly take a pain to give the details so that I may be in a position to use such remedy because since last one year I have to formate my system time to time due to such attacks;
    Thanking yo in an anticipation of your Co-operation,
    Syed Abdur Rahman

  22. Sunil Kumar RuiaJanuary 26, 2017 at 7:14 PM

    All viruses remove.

  23. let us thanks for this message

  24. syedkhaja multaniJanuary 30, 2017 at 10:46 PM


  25. very useful thanxs

  26. Mukesh BiswalFebruary 1, 2017 at 1:08 PM

    On behalf of my knowledge I have been heard that on WhatsApp there are pdf virus and video virus on it. Is it true.