Computer Virus: What is it, Types of viruses, Prevension

What is Computer Virus?

In today’s digital world, the term “computer virus” is well-known, but what exactly is it? A computer virus is a type of harmful software that can replicate itself and spread from one computer to another without permission. It is created by cybercriminals to damage, disrupt, or gain unauthorized access to computer systems or networks.

Computer viruses can come in different forms, such as executable files, scripts, macros, or disguised as legitimate software. Once a computer is infected, a virus can execute its malicious code, which can range from showing annoying ads to deleting files or even rendering a computer unusable.

Computer viruses can spread through infected email attachments, malicious websites, USB drives, social engineering tactics, and network vulnerabilities. They can target various operating systems, including Windows, macOS, Linux, and mobile devices. Some viruses can mutate and evolve, making them difficult to detect and remove.

Types of Viruses

Computer viruses come in different types, each with its own characteristics and behaviors. Here are some common types of computer viruses:

  • File Infectors: These viruses infect executable files and replicate themselves when the infected file is run. They can spread to other files on the same computer or through shared drives, removable media, or network connections.
  • Boot Sector Viruses: These viruses infect the boot sector of a computer’s hard drive or floppy disk. When the infected system is booted, the virus gets loaded into the memory and can spread to other disks or computers.
  • Macro Viruses: These viruses infect documents or templates that contain macros, commonly found in word processing or spreadsheet programs. They can spread when the infected document is opened and the macros are executed.
  • Polymorphic Viruses: These viruses can change their code or appearance to avoid detection by antivirus software. They can modify their code with each replication, making it difficult for antivirus programs to detect them.
  • Worms: Worms are self-replicating viruses that can spread through networks or the internet by exploiting vulnerabilities in software or using social engineering tactics.
  • Trojan Horses: Trojan horses are viruses that disguise themselves as legitimate software or files. Once executed, they can perform malicious actions, such as stealing data or damaging files.
  • Ransomware: Ransomware is a type of virus that encrypts a user’s files and demands a ransom for the decryption key. It can spread through infected email attachments, malicious websites, or compromised software.
  • Spyware: Spyware is a virus that secretly monitors and collects information about a user’s online activities without their consent, posing a privacy threat.
  • Adware: Adware is a virus that displays excessive and unwanted advertisements, disrupting the user’s browsing experience.
  • Botnets: Botnets are networks of infected computers that are controlled by a central server. They can be used for various malicious purposes, such as launching DDoS attacks or sending spam emails.

Common Signs of Computer Viruses

Here are the signs that may indicate the presence of a computer virus on your system in simplified language:

  • Slow performance: If your computer is suddenly running slower than usual, taking longer to start or load programs, it could be a sign of a virus. Viruses can use up system resources, like CPU and memory, which can cause decreased performance.
  • Unwanted pop-up ads: If you are seeing a lot of pop-up ads, even when you’re not browsing the internet, it could indicate the presence of an adware virus. Adware viruses show unwanted ads on your computer, often as pop-up windows.
  • Unexpected error messages: If you’re getting frequent error messages while using your computer, especially for programs or processes that were working fine before, it could be a virus infection. Viruses can interfere with normal program operations, resulting in error messages or crashes.
  • Homepage or search engine changes: If your web browser’s homepage or default search engine suddenly changes without your permission, it could be a sign of a browser hijacker virus. Browser hijackers modify web browser settings without your consent, redirecting you to unwanted websites or search results.
  • Missing or corrupted files: If you notice that files or folders on your computer are missing or corrupted, it could be due to a virus. Some viruses are designed to delete or corrupt files, which can lead to data loss or system instability.
  • Unusual network activity: If you notice unusual network activity, such as a lot of data transfers or connections to unfamiliar IP addresses, it could be a sign of a virus. Some viruses communicate with remote servers for malicious purposes, like stealing data or spreading to other systems.
  • High CPU or network usage: If you see unusually high CPU or network usage, even when your computer is idle, it could indicate a virus. Some viruses run background processes that use up system resources, resulting in high CPU or network usage.
  • Unauthorized access: If you suspect that someone has gained unauthorized access to your computer or online accounts, it could be due to a virus. Some viruses are designed to provide remote access to hackers, allowing them to control your computer or steal your personal information.

How Do Computer Viruses Attack and Spread?

Computer viruses are malicious software programs that infect and compromise computer systems. They spread through various methods, including:

  • Email attachments: Viruses can spread through infected email attachments. When users open these attachments, the virus can execute and infect their computers.
  • Infected removable storage devices: Viruses can also spread through infected USB drives or external hard drives. When an infected device is connected to a computer, the virus can execute and infect the system.
  • Malicious websites and downloads: Viruses can be distributed through infected websites or downloads. When users visit infected websites or download infected files, the virus can be downloaded and executed on their computers.
  • Social engineering and phishing attacks: Viruses can spread through social engineering and phishing attacks. For example, a virus may be disguised as a legitimate software update or file, tricking users into downloading and executing it.
  • Network vulnerabilities: Viruses can exploit vulnerabilities in computer networks to spread from one computer to another. For instance, if one computer on a network is infected, the virus can propagate through the network and infect other vulnerable computers.
  • Software vulnerabilities: Viruses can exploit security flaws in software programs or operating systems to gain unauthorized access and spread. These vulnerabilities are often discovered and exploited by hackers.
  • File sharing and peer-to-peer networks: Viruses can also spread through file sharing and peer-to-peer networks. When users share infected files or download files from infected sources, the virus can be transmitted to their computers and execute.

How To Prevent Your Computer From Viruses

To protect your computer and network from viruses, it’s important to follow these tips:

  • Install antivirus software: Antivirus software can detect, prevent, and remove viruses. Keep it up-to-date and perform regular scans.
  • Update your operating system and software: Keep your operating system and software updated with the latest security patches to protect against known vulnerabilities.
  • Be cautious with email attachments and downloads: Avoid opening suspicious email attachments or downloading files from untrusted sources. Verify sender authenticity and scan attachments or downloads before opening.
  • Be cautious online: Avoid clicking on suspicious links or visiting malicious websites. Stick to reputable websites and download software from trusted sources.
  • Use strong passwords: Use strong and unique passwords for all your accounts, including computer and network login credentials, to prevent unauthorized access.
  • Regularly back up your data: Back up your important data to an external source or a cloud-based service regularly to restore files in case of a virus attack.


What is a computer virus?

A computer virus is a type of malicious software that infects and compromises the normal operation of a computer system, potentially causing harm to data, files, and the overall functioning of the infected system.

How do computer viruses spread?

Computer viruses can spread through various methods, such as email attachments, infected removable storage devices, malicious websites and downloads, social engineering and phishing attacks, network vulnerabilities, software vulnerabilities, and file sharing or peer-to-peer networks. They can also exploit vulnerabilities in software programs or operating systems to spread.

What can computer viruses do?

Computer viruses can perform various malicious activities, such as stealing sensitive data, corrupting files, disrupting system operations, providing unauthorized access to hackers, or spreading to other computers on a network.

How can I protect my computer from viruses?

To protect your computer from viruses, it’s important to use updated antivirus software, avoid opening suspicious email attachments or downloading files from unknown sources, keep your software and operating systems updated with the latest patches and updates, practice safe browsing habits, and be cautious of social engineering and phishing attacks. Regular data backups can also help mitigate damage caused by viruses.

What should I do if my computer is infected with a virus?

If you suspect that your computer is infected with a virus, take immediate action. Run a reputable antivirus scan to detect and remove the virus. If the virus has caused damage to your files or data, you may need to restore them from a backup. It’s also essential to change passwords for your online accounts to prevent further unauthorized access.

Can I get a virus even if I have antivirus software installed?

Although antivirus software provides significant protection against viruses, it’s not foolproof. New viruses are constantly emerging, and some may bypass antivirus detection. Therefore, it’s important to keep your antivirus software updated and practice safe computing habits to reduce the risk of virus infections.

Can viruses affect mobile devices or other devices besides computers?

Yes, viruses can infect mobile devices, such as smartphones and tablets, as well as other devices connected to the internet, such as smart TVs, routers, and IoT (Internet of Things) devices. It’s crucial to take appropriate security measures, such as using reputable antivirus software and keeping all devices updated with the latest patches and updates, to protect against virus infections on various devices.


It’s crucial to take appropriate measures to protect your computer from viruses, such as using updated antivirus software, practicing safe browsing habits, keeping software and operating systems updated, and being cautious of suspicious emails and downloads.

In case of a virus infection, prompt action, such as running a reputable antivirus scan and restoring files from backups, is necessary. By staying vigilant and taking proactive steps to safeguard your computer, you can minimize the risk of falling victim to a computer virus and protect your data and system’s integrity.

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