Home Uncategorized Everything About Computer Viruses – Detailed guide 2020.

Everything About Computer Viruses – Detailed guide 2020.


The computer virus is a program file that is capable enough to make its own code without the knowledge of the user.

Then the virus can copy itself to other files or disks and make changes on your computer.

Whats in it for me?

  1. What are computer viruses?
  2. Types of computer viruses.
  3. How viruses affect computers.
  4. History of computer virus.
  5. How antivirus find viruses.
  6. How to protect your computer from viruses.
  7. Conclusion.
  8. FAQ.

What is a computer virus?

A virus is a program file that is capable enough to make its own code without the knowledge of the user by linking the file to the document.

When the file or document that runs destroys others files also and spread to the computer slowly and steadily.

viruses are just the same as the viruses or the diseases that attack the human body, they also directly or indirectly destroys our body the same case is that with the viruses.

Execution of host program file results in the execution of viruses.
Needs human action to execute.

The structure of Computer Virus is divided into four parts –

  1. Mark
  2. Infection Mechanism
  3. Trigger
  4. Payload

Types of computer virus. –


There are following basic categories of viruses –

Macro Viruses –

These viruses infect all the files that contain macros.

For example – doc, PPS, Xls and MDB, they affect the macros, templates and
also, the documents that are present in the files.

Some example of macro virus are –

  1. Relax.
  2. Bablas.
  3. Melissa, A.
  4. 097M/Y2k.

Memory Resident Viruses –

They attack inside the computer memory, so it gets activated
when the operating is running and infects all other files,

The most important thing is they are hidden in RAM.

Also read – Computer memory types.

Some example of Memory Resident virus are –

  1. CMJ.
  2. Meve.
  3. Randex.
  4. Mrklunky.

Overwrite Viruses –

These viruses delete the efficient information available in a
file, therefore, at the end it leaves the file fully or half useless, it replaces
the content but do not change the size of the file.

Some example of Overwrite virus are –

  1. Trj.Reboot
  2. Way
  3. Trivial.88.D

Direct Action Viruses –

These types of virus duplicates and takes action when they are
executed, also, they infect the files in the directory or the folder in it

( AUTOEXE.BAT ). they are found in the root directory.

Some example of Direct action virus are –

Vienna virus

Web Scripting Virus –

Mostly the web pages include complex codes with the purpose
to create an interactive and interesting content, but

these codes are used to create unwanted actions, also, it comes from infected

Some example of web scripting action are –

JS.Fortnight – a virus that spreads via malicious

FAT Virus –

They attack the file allocation table (FAT) which is the part to
store every information.

They do their own encrypting and programming in a different style when they infect the computer,

Also, they use different encryption and algorithms, as a result it makes it difficult for the antivirus to trace it.

Worm –

This program has the property of self-replication causing negative effects on the computer.

Trojans –

Trojans can unapproved tracing of important login details of users online, also called Email Virus. Because this virus spread through email.

This virus hide in an email and when the receiver receives the mail it is spread widely

Browser Hijacker computer virus –

It can be spread while downloading. also, it affects the browsers
functioning of basic redirection of the user to certain sites.

For example – the cool web search, Boot Infectors.

How viruses affect computers –

Stage I – Creation – The Computer viruses are created by
peoples who wish to cause damage to computers.

Stage II -Replication – Computer Viruses duplicates itself and
transfers from one pc to another pc.

Stage III -Activation -The damage causing viruses activates
itself when the conditions are successfully met for it.

Stage IV – Discovery – It takes place once a year at least when
the virus has
become a threat.

Stages V -Assimilation – At this point of time antivirus developers detect the remedy to cure the virus, this may take a time period of one to 6 months also.

Stage VI -Eradication – If any user installs the proper software to delete the viruses it can be successfully deleted, but the fact is that not any virus is deleted completely but its effect is reduced.

History of computer viruses –

Virus attacks are not shocking news anymore. But here is the list of the worst
of those attacks which shocked many at that time in history. ]

The history of computer virus attack is as follow –

Jerusalem [1998] – This was the first MS-DOS virus that caused huge
damages, hitting many countries, universities, and companies worldwide.

Morris [1998] – This computer virus infected over 6,000 computer systems in
the United States, including the famous NASA research Institute, as a result for some time, remained completely closed.

also, damages caused by the Morris computer virus were estimated at $96 million

Solar Sunrise [1998] – In 1998 using a computer virus so, hackers, grasped
and took control of over 500 computers systems that belonged to the army,
government and private sector of the United States.

CIH [1998] – Unleashed from Taiwan during the year 1998. Above all CIH is recognized as one of the most dangerous and destructive virus ever.

Melissa [1999] – It was created by David L. Smith earlier in 1999 and based on a
Microsoft Word macro. also, he intended to spread the virus through e-mail messages.

ILOVEYOUILOVEYOU [2000] – It was a standalone program that was capable of replicating itself. Also, the virus initially traveled through the e-mail, the same way
as Melissa virus.

Code Red and Code Red II [2001] – It exploited operating system vulnerability found in Windows 2000 and Windows NT machines. due to the buffer overflow problem was the vulnerability.

Downadup [2009]– The latest and most dangerous virus is the “Downadup
worm, which also called “Conficker”. Also it infected 3.5 million computers worldwide.

Wanna-cry ransomware [2017]- wanna cry ransomware down all the computers running on Windows XP and effect all the ATM machines and government computers.

How to protect your computer from viruses. –

Time needed: 30 minutes.

How to protect your computer from viruses.

  1. Secure your computer.

    Keep your windows defender activated as it could
    protect the system from any malicious activity occurring

  2. Use antivirus.

    use anti-malware app and also keep it updated(basically anti-malware app check for viruses, spyware and any other threatening events occurring
    within the system which could interrupt its

  3. Avoid opening popup.

    use of pop-up blocker is useful.

  4. Check computer notification.

    we should pay attention to all the notification.

  5. use smart screen while using internet

    the most important thing is, if we are using Internet Explorer we should ensure that a Smart screen is turned on.

  6. Update your windows.

    windows should be updated and it should be the genuine windows.


Virus basically destroys our system due to which our important
information lost.

It also creates multiple copies of the same data that creates pressure on the computer and the computer becomes slow.

so we should always keep our firewall and antivirus updated.


Which computer virus is the most dangerous?

Ransomware is the most dangerous virus. Most importantly wanna-cry ransomware makes a huge destruction in the year 2017.

Who creates PC virus?

All viruses are man-made. also, viruses are made sometimes just for fun.

When was first computer virus invented?

The first IBM PC virus in the “wild” was a boot sector virus dubbed Brain, created in 1986 by the Farooq Alvi Brothers in Lahore, Pakistan.

Will restoring computer remove virus?

Yes, you can reset or format your computer it will remove all kind of viruses.

Where viruses come from?

it generally, comes from prated files and email. So stop downloading pirated files.
Also stop opening unusual emails.



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