What Is a Computer Virus? Types Of Computer Virus Ultimate Free Tutorial 2021

what is a computer virus

Hello friends, I am Anand Patel, here we are going to talk about virus what is a Computer Virus, types of computer virus, and preventions to secure our computer from virus

If you are a mobile, computer, or laptop user, then you must have faced the issue of slow system speed, corrupt files, system hang issue, software crash, and many more, these all may cause because the virus in your system.

Viruses are malicious software or programs that are intentionally developed by developers, programmers, or hackers to corrupt user’s data or steal user’s information from their computers or other devices.

If you are here that means you have questions about computer viruses like what is a Computer Virus, types of computer viruses, effects of computer viruses, and what are the preventions of the virus, so read this post till the end, and you will get your all answers, and many more

What Is Malware

Malware Definition And Meaning

Malware is known as malicious software, these are computer programs that are designed to corrupt files and damage computers without the user’s consent.

Malware is a general term that is used for covering all the different types of threats that corrupt your files or damage computer such as virus, spyware, trojans, worms, rootkits, and so on.

These malicious programs can perform a variety of functions like stealing information, encrypting or deleting important data, hijacking core computing functions, and monitoring a user’s computer activity without his permission.

Malware comes in our computer form downloading wrong and corrupt files, spam emails, unsecured and malicious websites.

If your system is working slow and not performing well, then you must read our post on how to speed up your computer and make it superfast, this post can help you a lot in speeding up your system.

Types Of Malware

  • Virus
  • Worms
  • Trojan horse
  • Ransomware
  • Spyware
  • Adware

here we will learn different types of malware one by one in detail.

What Is a Computer Virus

Here we will learn the meaning and definition of computer virus =>

Meaning Of Computer Virus

The full name of the virus is Vital Information Resource Under Siege. A computer virus is a program or software that is developed by a programmer or hacker to corrupt, damage or steal the data and information of the user’s from their computers.

Programmer or hackers develop these type of programs(viruses) and spread them on the web through websites, email, link, and with other software, and once user click on those links, or download and install those program, directly or indirectly with other software or files,

Then these virus starts damaging your system’s files, folders, programs, the virus can create duplicate copies of your files, delete files, move to other places, make your system slow, hang your system, crash hard drive, and send the information of your system to the hackers.

Definition Of Computer Virus

What Is a Computer Virus?

Viruses are malicious software or programs that are intentionally developed by developers, programmers, or hackers to corrupt user’s data or to steal user’s information from their computers or other devices.

“A computer virus is a type of malicious software that, when executed, replicates itself by modifying other computer programs and inserting its own code. When the replication succeeds, the affected areas are then said to be infected with a computer virus.”

The first virus that was spread on the internet network was Creeper, that was developed by Robert Thomas in 1971, creeper didn’t harm computer and files, it just interrupted users form working, whenever they start their work, again and again, they got a pop-up of “I am Creeper catch me if you can”

At that time, it was called prank software, but as time passed and so many malicious software came on the internet, then these were named viruses.

The first virus that was spread on the computer was ELK CLONER VIRUS, which was developed by rich skrenta in 1982, ELK Cloner virus was developed for Apple II(DOS 3.3) OS.

ELK Cloner virus was used to be stored in floppy dick and used to infect boot sector of the PC.

If you have been cheated on the internet or want to be safe then you must read our post on what is phishing attack and how to become safe, this will make you informed about all internet frauds.

Types Of Computer Virus

  • Boot Record Virus – This type of virus stores in the boot sector of the computer, and when we start our computer, then boot record virus automatically becomes active with the computer and slower the booting process and computer speed, to remove this type of virus from the computer we need to format our computer.
  • Direct Action Virus – This type of virus directly installs in our computer from the internet, and starts deleting system files, restart the computer, again and again, also interrupt the internet from starting by deleting its drivers, and so on.
  • Multipartite Virus – This type of virus automatically execute the programs and files of the computer, harm the boot sector of the system, and sometimes crashes the computer.
  • Polymorphic Virus – This virus creates so many copies of itself with deferent names in deferent folders, and fills all the space of the memory from its copies so that the computer starts hanging.
  • Overwrite Virus – This virus deletes the data of original files and overwrites the data with corrupted data, so whenever you open that file, you didn’t find the original data on that file.
  • File Infector Virus – This virus doesn’t overwrite the data of the file but deletes the original file, and at the place of the original file creates an empty duplicate file, so whenever you open that file you didn’t find that data.
  • Macro Virus – Macro is a function in MS office where we can create files and store them in it, macro virus attacks on MS office’s files.
  • Resident Virus – It creates two copies of itself and stores them in deferent places on the REM memory, so this becomes difficult for antivirus to detect them, if one copy of resident virus is detected by the antivirus, so it creates another copy of itself and stores it in another place on the RAM, and become resident on the computer, that’s why it is called a resident virus.
  • Rootkit Virus – This is a so much dangerous virus when someone downloads any file or software from any illegal or unsecured site, so this virus automatically downloads into the computer with that software, rootkit virus creates back doors and loopholes for hackers so that hackers can easily hack the computer and steal important information from the computer.

Symptoms Of Computer Virus

Now we know what is a computer virus and what are the types of computer viruses, but how will you detect them or how will you know that your system is infected from viruses, here are some symptoms that indicate that your system is infected by virus =>

  • System performance – When viruses attack the computer and corrupt the files of the computer, then the computer becomes slow, and the slow performance of the computer is an indication that your computer may be infected from viruses.
  • Pop-ups on-screen – When you, again and again, see pop-ups on your computer’s screen without allowing pop-ups on any website or app, then this may be because of viruses.
  • Copies of files – If you see different copies of files in different places on your computer that you haven’t created, that means viruses are creating these copies of files.
  • Autostarting of programs – If files and programs are automatically starting on your computer without performing any action, then this may be because of viruses.
  • File not open or missing – If programs or files are not opening or missing, and you haven’t deleted them, then this may be the work of viruses.
  • Sound from hard disk – Normally our computer’s hard disk never makes any noise, but if it finds an attack of dangerous viruses, then sometimes it makes a sound, and this is an indication of a viruses attack.

Here we have learned what is a computer virus and types of computer virus, now we will learn some other types of malwares

If you want to make your internet browsing private and secure then you must know about VPN virtual private network that can make you anonymous on the internet.


What Is a Computer Worm

If you think about small creeturs (worms) that we use as bait for phishing, so those worms are not harmful, but if we talk about computer worms, then these computer worms are so much dangerous, computer worms are not as much destructive as a virus, but they are as dangerous as a virus.

Worm Definition

“Computer worms are small programs or pieces of software that create so many copies of themselves, worms don’t target any particular computer, but they aim to infect the whole network of computers.”

A computer worm is a small and independent malicious program that doesn’t need any host file and any call to action, computer worm itself creates so many copies of it and spread on all over the computer network like files, folders, address, emails and so on,

And, when we connect any Pendrive or DVD or any other device with our computer then worm copies itself with other files and spread in those devices.

Most worms are designed to infiltrate systems while very few worms also try to change the system settings, even if they don’t do this but they are still very dangerous as they take up a lot of bandwidth and other valuable resources.

Worm VS Virus

Computer worms and computer viruses both are types of malware, but they are not same they have some differences as described bellow =>

  • Computer viruses by definition target individual computers whereas worms target networks of computers to create botnets.
  • While viruses are usually bundled with legitimate files or programs, computer worms are stand-alone and don’t need any host file.

Example Of The Computer Worm

One example of a famous worm is the I love you worm, love worm is sometimes referred to as love bug or love letter for you, this was a computer worm that infected over 10 million windows personal computers on and after May 4, 2000, it started as an email message with the subject line, I love you and the attachment love letter for you.DXD.VBS

Opening the attachment activates the visual basic script, the worm inflicts damage on the local machine overriding random types of files and sends a copy of itself to all addresses in the windows address book used by Microsoft outlook, this made it spread much faster than any other previous email worm.

Trojan Horse In Computer

Trojan Horse Meaning

Trojan horse is also a type of malware, this is a so much dangerous and destructive malware, once it is installed in your computer then it can delete, remove, duplicate files and programs, it can format C drive of your computer, corrupt hard drive, and can damage the whole system, so that computer may stop working.

Trojan Horse Definition

“Trojan horse is a fake malicious software that comes in computer from the illegal and unsecured website, it can delete, remove, format files from computer and can completely damage our system.”

Whenever someone opens illegal or unsecured, malicious websites he gets a pop-up “your computer has dangerous viruses download this software to remove them”, “50000$ awaiting for you click on this link to grab it”, and so on like this, once the user clicked on that, a fake software downloads in their computer, that looks like the software but it is a trojan horse.

once it installed in computer then it can damage the whole system that computer will stop working.

If you want to know what is rooting in android and should you root your phone or not, then read our post on it to make a better decision.


What is ransomware on the computerRansomware is malicious software, that is developed by the hacker to block computers, once it is installed on a computer then it completely blocks/locks or stops the computer from working, it also leaves a message or file with the title please read me,

In the message, it informs that what happened to the computer, and asks to pay the hacker to repair or unlock the computer, it also tells the due date to pay the amount, and if the amount is not paid till due date then hackers increase the amount

The amount is asked to pay in virtual currency like bitcoin, and till the money is not paid computer keeps in locked condition.


What Is Spyware – Spyware is a small malicious program that comes into our system through emails, malicious websites, and other files and software.

Spyware works like a spy on our computer and sends small pieces of information like system activity, username, password, emails, and history of visited websites.

This is so much dangerous malware as it directly sends all our important information to the hacker, and the hacker can misuse all this information.

Without any premium antivirus, you can not detect spyware, so if you want to remove spyware from your computer, so you must need a powerful premium antivirus or format your computer.


What is Adware – Adware is a malicious software application that shows advertising banners, pop-up ads whenever we run any program on our computer,

Adware shows pop-up ads, bar ads, full-screen ads on the user interface, most of the adware are developed for computers but some adware also runs on android devices and shows ads on that.

Most of the adware is developed to interrupt the user from work, as they only show ads, again and again, on the screen, adware doesn’t aggressively affect our computer’s files, as their main motive is to interrupt the user and showing ads on the screen.

What Are The Preventions Of Viruses And Malware

We have understood what is a computer virus, and other malware, and how much danger they are, but what are the preventions, how can we secure our computer from viruses and malware, there are some things that you should do and shouldn’t do to secure your computer, these are =>

What Should Do =>

  • Antivirus – Antivirus works for the safety of our computer, but if you have any free, basic antivirus, then it may be not capable of the catch-all type of viruses and malware, if you want to secure your computer, then you must have a paid antivirus, that can find and remove all viruses, and male ware from the computer.
  • Unknown Email – If you have received any unknown mail then first inspect it, and never click on any link given in it as it can have malicious links, that can install viruses and malware.
  • Unknown Or Unsecure Site – If you are visiting any illegal or unsecured site, then don’t download any file, song, movie, or software from that website, you should always download things from a trusted and official website.
  • Scan File Before Installing – If you have downloaded any file or software, then before installing it, you scan it, as so many files also have viruses with them.
  • Malicious Pen Drive Or Device – If you connect a pen drive and other devices with your computer then it should be your own or a trusted device, never connect any unknown device with your computer as it can have viruses, that can infect your computer.
  • Secure Browsing – If you surf the internet, then you should always use a safe and secure browser to surf the internet, as most of the viruses and malware come into our computer from the internet, and the lack of security of the browser makes it easy for them.

What Shouldn’t Do =>

  • Don’t access the internet without antivirus.
  • Don’t open unknown source emails.
  • Don’t visit the illegal and unsecured websites and other websites that attract you through lust, offer, money, and so on.

If you want to improve the work efficiency of your browser then you must know about the extensions and the best chrome extensions that can enhance the work efficiency of your browser.


We have learned what is a computer virus, what is malware, their types, and so on, but most of the viruses and malware come into our system because of our negligence, so always be careful about those viruses, and always do safe browsing, never download unsecured files or software from any unsecured site.


  1. I’m not sure the place you’re getting your info, however good topic.
    I must spend some time studying much more or figuring out more.
    Thank you for excellent info I was searching
    for this information for my mission.

  2. Hello, this weekend is pleasant in favor of me, as this point in time i am reading this wonderful educational post here at my residence.
    0mniartist asmr

  3. It’s very simple to find out any matter on net as compared to textbooks,
    as I found this piece of writing at this web page. 0mniartist asmr

  4. Great post. I was checking continuously this weblog and I am impressed! Very helpful information specially the final section 🙂 I maintain such info much. I used to be seeking this particular info for a long time. Thanks and best of luck.


Please enter your comment!
Please enter your name here