Types Of Computer Viruses And Their Painful Effects

Through this post, I’m going to discuss the types of computer viruses and their painful effects on PC. I hope it will help you to protect your computer from hazardous programs. 

Nowadays, the use of computer and internet has been rapidly increased. Together with it, the computer threats like spyware, Trojans and worms are rising and get into the action severely.

So it is good to know the various types of computer viruses to protect your system from the malicious programs. Let me start the discussion in my familiar writing style with a basic question.

What is Computer Virus?

A biological virus makes you sick! Like the same, computer virus infects your programs and files on your PC. Yes, it is an executable program which affects the normal operation of the computer by damaging the contents of the hard disk. It could cause frequent computer crashes, delete files, weakens computer memory and even reformatting the hard drive.


How Do Computer Viruses Reach You?

Different types of computer viruses would reach you through the typical web activities like,

1. Opening email attachments from fake accounts.

2. Clicking inappropriate internet advertisements without understanding fully.

3. Installing/downloading the free games, toolbars or system utilities.

4. Visiting an infected web page

5. Setting up of software without license agreements and so on.

Not only with web activities, if you are not running the latest updates of your operating system and not using the good antivirus software, computer viruses would reach you easily.

 Read: A Simple Guide about Anti-virus program

Different Types of Computer Viruses

Many types of viruses exist, and some famous viruses types are

1. Macro Virus

Macro virus is a type of email virus which mainly targets to infect the programs that contain Macros like Microsoft Office files. These are mini-programs that have the power to affect the template and document of that file.

2. Memory Resident Virus

Memory resident virus automatically fixes themselves in the computer memory, and if the operating system started to run, it gets activated. It hideout in the computer memory and allocates space to execute its code. It can easily corrupt the files that are recently used.

3. Multipartite Virus

The multipartite virus spreads in multiple ways and infects the programming files. They used to hide in the memory like Memory resident virus and do affect the hard disk.

4. Polymorphic Virus

A polymorphic virus is a powerful virus that might guard itself with an encryption algorithm and has the tendency to change automatically when certain conditions are meet. Because of having the encrypting capability, it is tough to find it by even with an antivirus program.

5. FAT virus

FAT virus spoils the file allocation system section (Information where the location of data and the details of the available spaces are stored) and might cause crucial damage to it. It would result in defeating the individual files or complete directories.

Not only these! There are still some common types of computer viruses like Web scripting viruses, Boot sector viruses, time/logic bombs, direct action viruses, Trojan horse virus, Root kits, spywares, and worms have affinity to disrupts the computer operation.

Most Dangerous Computer Viruses

In late 1980’s, computer viruses have started to born. Did you know about the first computer virus? It is “The Brain” released from Pakistan in the year 1986. So the 25th anniversary of the first PC virus was marked in 2011.

The danger rating of the first computer virus is very small, but the most dangerous viruses came into existence in 1990’s. Let’s check some worst types of computer viruses now.

1. Code Red

A powerful worm named “Code Red” had made the anti-virus researchers in hindrance, and it infected millions of computers and lakhs of servers. It took advantage in Microsoft Internet information server too and was first detected by the employees of eEye digital security. It is not necessary to open an email attachment or execute a file, it catches your PC if you open a particular web page.

2. Melissa

Melissa is a well-known worm that infected the MS Word document files through email attachments using MS outlook. This virus caused a severe destruction to the computers in 1999, and the damage was estimated at millions of dollars. It had made the modern concerns like Intel and Microsoft temporarily to shut down.

3. My doom

My doom was considered a powerful virus in 2004 as it had the proficiency to stop accessing the antivirus program by the operating system. This virus spread through email with the text “Mail transaction failed” and gets downloaded into the system once the message got clicked. Millions of computers were infested through this virus and loss was estimated in billions.

4. Nimda

Nimda virus had risen in the year 2001, and it is just the reverse form of the word “Admin”. This virus targeted to slow down the internet traffic, and it propagated to the system in different ways through emails, while sharing files, server weakness, etc. Once this worm gets activated on the computer, the attacker would have the full control to the system if certain conditions are meet.

5. Conficker

Conficker is the widespread internet virus and so the anti-virus researchers called it as “Super worm”. This dangerous virus targeted Microsoft operating systems, and so millions of computer that had vulnerable Windows OS had hit by it. This worst virus might spread through removable drives and assembled in such a way to take the financial and other vital data from the system.

If you’re are using computer from long, then you might be aware of some other worst types of viruses like I love you (2000), Stuxnet (2009), agent.btz (2008), SQL Slammer (2003) and Blackworm (2006).computer-viruses-types                                                                                        Image credit: Flickr.com

Types of Computer Viruses in 2012

Now, do check some types of computer viruses which caused significant damage to the computers in the year 2012.


Shamoon was discovered in August 2012 that has been used for cyber spying. It infects the system runs on Windows NT, Windows me and Windows 9x. The attacker uses the “dropper” function to spread in the network to the hard disk of the computer so that to compile the list of files on attacked computers.

Then the attacker receives the data with the help of “reporter” program. “Wiper” is the function used to erase the involved files and this might create problems in booting by overwriting action.


Gauss is the highly destructive computer worm which was intentionally created to steal the data from Middle-east banks. It was discovered in June 2012 by a Russian lab and it affected thousands of computers.

It can infect the USB drives and collected information will be stored as a hidden file on the removable drives.

DNS changer

Cyber-criminals created this virus to redirect the internet traffic to a phishing website. The DNS changer computer virus modified the Domain Name System (DNS) configuration of computers and redirects the users to a specific website.

FBI got involved in this virus and the interim servers were official shutdown on July 9, 2012.


Belgian is the worst computer virus spreads through spam emails or hacked webpages. It locked the computers and then asked for some money to unlock the data.

This global virus has the power to gain the remote access to computers to track the files and launch the malware when Windows gets started.


Flame is the complex malware found in 2012 which used Bluetooth to send commands. It was discovered in Russian lab and it grabs the data from chats, emails and screenshots.

It steal sensitive data and infects many computers in Iran and Middle east countries.

Many types of computer viruses are being created everyday and the new computer virus like Ransomware (freezes the PC and ask to pay ransom to unlock) have started to cause damage to the computer this year. Even though the anti-virus researchers are working to prevent these actions with powerful anti-virus software, cyber-criminals are tactically creating the malware.

 Read the recent Economic Times article related to Ransomware


How vulnerable are we? With new technology advancements, highly skilled programmers invents several types of computer viruses to damage our computer or to steal information from it. Computer Viruses are the well-known computer attackers and they can drastically slow down its operation.

Moreover, due to the easy installing nature of malicious programs, computer users suffer with the data loss and system disruption. So it is essential to take some security measures by installing effective anti-virus software to ensure your computer protection.

I had been greatly suffered by some types of computer viruses last year and now protected my system with Quick heal Total security antivirus software.

It has some advanced programs and upright in system cleaning. I suggest you to opt premium virus protection than using free anti-virus software. I hope that you’ve gained some knowledge about the types of computer viruses and their painful effects through this post and now its your turn to share your insights/experience in the comment section. 

30 Comments (click here to leave a comment)

  1. Ryan Biddulph

    Hi Nirmala.

    Good breakdown here buddy. I had a virus a few weeks ago here in Pondicherry. It was rough! I was really sick to my stomach but after a few days all was good.

    Similar effects plague your computer if you catch a virus. As you said, get the proper protection, educate yourself and please, no clicking on untrusted links.

    Unless you know a person well never click on attachments. Even if you do know a person well and the attachment seems suspicious, call them or connect with them through some other social network to verify if they in fact sent it.

    Great tips buddy, thank you.

    Ryan Biddulph recently posted…3 Tips for Skyrocketing Your Affiliate Sales QuicklyMy Profile

  2. Madam this article is so depth that makes us to get each and every virus clearly. Thanks for pointing out. I have good experience with these. And never for browsing in internet without installing anti virus. These would surely give a bad impact in our system.

    Notepad also helps to detect some viruses. Pointing out latest computer viruses in 2012 also wonderful. An updated article on computer Trojans thanks.
    Tharun recently posted…Limit Login Attempts in WordPressMy Profile

  3. What hurts me most is viruses from emails. I have never understood why the email address providers can’t find a way to deal with this things and people who post and send them. I once experience two tough days because of opening an email in 2011, ‘A total damage’ I had not backed up my infor and you can bet the pain I went through plus spending money which I had not planned. I learnt my lesson. Thanks for sharing ~ Anetta

  4. From my experience, sometimes you might not even know that your computer is infected with a virus. I also met a lot of people who believe that having an antivirus software on the computer can protect them from anything on the web so they go clicking any link they find, harmful or not.
    I wish more people realized that antivirus reduces the chances of getting a virus, but doesn’t completely eliminate it. New viruses are being written every day, and antivirus software is just playing catch-up most of the time.

  5. Hi, Nirmala Mam,
    Indeed very informative post. :)

    Yes, viruses are very dangerous for personal computers and personal data. Through these malicious programs, hackers try to reach our data and then they hack.

    These programs mainly come from untrusted source or mail on internet.
    Know about these Viruses can helps us in saving our vital information from being hacked.
    Thank you very much for sharing such a wonderful Post.
    Have a great weekend. :)
    Kumar Chandan recently posted…Is Page Rank End?My Profile

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