Top 5 Computer Viruses for Windows in 2021

Everyone who used PC for even once has heard of computer viruses and knows that viruses are not something good. In order to prevent computer viruses invading your PC, you should regularly check-up your computer`s health. Most of the times, virus invasions can be fixed by installing an antivirus program and scanning your files and system.

However, sometimes that is not going to be enough. In some cases, the result can be a total disaster. Then, your PC becomes unusable and you can only throw it away, and acquire another. Furthermore, these viruses can do even more damage by stealing your personal data. We are going to introduce you to the five most dangerous computer viruses as of 2021.

Computer Virus #1: Code Red

Code red is a computer virus that emerged in the early `00s. It was stumbled upon by eEye Digital Security employees. It was named after a drink called Code Red Mountain Drew that was consumed by two persons that discovered this virus. The modus operandi for this one is that it multiplies itself so much that eats all of the resources of the computer.

The virus itself is not leaving almost any trace on the hard disk, by running on the memory almost entirely. It has one of the most unforgettable symptoms. It is the message displayed behind the websites that are hacked by this virus. It shows a blank page with a sentence that says: “Hacked by Chinese”.

Computer Virus #2: .Adobe Ransomware

.Adobe Ransomware is a computer virus that is considered to be a spin-off of Dharma Ransomware, a data locker that appeared for the first time in late 2018. The virus enters the Windows Registry and launches and represses all the process in the whole of the operating system. It locks and encrypts files. Luckily, there is a solution to this virus, and you can find ransomware virus removal instructions on the internet.

This virus is targeting a lot of types of files and data:


  • Image Files
  • Video Files
  • Banking Credentials
  • Personal Data
  • Audio Files
  • Backup Files


Computer Virus #3: ILOVEYOU

Now, we are going to talk about a virus that is considered to be one of the most dangerous you can pick up while surfing on the internet. Its name is ILOVEYOU. As of today, this virus made serious damage to various systems all over the world. Recently, there was a research that had the task of finding out how much damage this virus caused. It was ten billion dollars. Yes, it was that high.

It is believed that around ten percent of all computers that are connected to the internet were infected by ILOVEYOU. There are two creators of this virus, two Filipino programmers, Onel de Guzman, and Reonel Ramones. Since there weren`t any laws against malware, the two of them were never charged for anything.

Computer Virus #4: Melissa

A virus named after an exotic dancer, Melissa, is probably one of the best-known computer viruses. It was created in 1999, by David Smith. Its first form was a Word document that was infected and put on a group called* UseNet. If a PC user clicks on it, the virus will enter his computer and start spreading through the computer.

Almost immediately, Melissa will mail itself to fifty contacts from the address book of the user, and by that, spread itself to other machines. The virus caused around 80 million dollars of damage. The creator, David Smith was arrested. He collaborated with the FBI in arresting other computer virus creators. Probably, the most famous was an arrest of the creator of Anna Kournikova virus.

Computer Virus #5: Zeus


Zeus is a computer virus that was identified in 2009. It is a trojan that attacks the operating system and performs numerous criminal acts, such as form grabbing and browser keylogging. Most of the machines that were infected by this one, were infected via phishing scams or drive-by downloads. Zeus attacked many computers of big banks and corporations, like Amazon, Cisco, etc.

There is no precise information about the damage it caused. Still, we have some information. In the United States, about 25% of all PC was infected by this virus, and the damage was around 1 million dollars. In eastern Europe, there was its operations resulted in 70 million dollars of damage. Around a hundred people were arrested in the process.