10 Symptoms of Computer Viruses: Most Common

Last Updated on 4 months by Touhid

A computer virus is a malicious code or program that attacks a computer. There are several symptoms or signs of computer viruses. In this article, our experts will show you a list of 10 symptoms of computer viruses, which will ensure that your computer may have a computer virus.

So, keep on reading about the symptoms of computer viruses to learn more.

What are the Computer Viruses?

A computer virus is a type of malware that harms your computer system such as deleting files, encrypting, files turned into shortcuts, formatting the hard drive, and flooding network traffic.

The main purpose of creating a computer virus is to infect vulnerable systems, access admin control, and steal sensitive information.

The common types of computer viruses in the computer are as follows:

  • Boot Sector Virus
  • Direct Action Virus
  • Resident Virus
  • Macro Virus
  • Multipartite Virus
  • File Infector Virus
  • Browser Hijacker
  • Polymorphic Virus
  • Web Scripting Virus

To learn more about common types of computer viruses.

10 Symptoms of Computer Viruses

The most common 10 symptoms of computer viruses are as follows:

  1. The computer is Slowing Down
  2. Unexpected Pop-up Windows Appearing
  3. Unwanted Programs Start Automatically
  4. Missing Files and Programs
  5. System Crashing
  6. Out of Storage Space
  7. Computer Malfunction
  8. Blocked From Antivirus Sites
  9. Advertisements on Web Browser
  10. Files Turned into Shortcuts

10 symptoms of computer viruses

Computer is Slowing Down

Computer slowing down is one of the most common symptoms of computer viruses. If your computer is taking longer time than normal to start and internet speed begins to slow down, then your computer has been affected by a computer virus.

Expert Tips

If your computer’s performance is sluggish, then first check the RAM or hard disk space. If there is not enough size or space, then it is sure that your computer is infected by a virus or malware.

Unexpected Pop-up Windows Appearing

Unexpected pop-up windows are another symptom of computer viruses. The appearance of unexpected pop-up windows on your computer is another irritating symptom of a computer virus, which is indicative of a malware attack on your computer.

Computer viruses, malware, and spyware can infect your hard disk result in pop-up ads, and slow your computer’s performance.

Expert Tips

It is suggested that never click on suspicious pop-up windows even if it says “a virus has been detected”.

Unwanted Programs Start Automatically

When you start your computer, you may become aware of some unwanted warning signs that mean your computer has been infected by a virus. The symptoms may be windows shutting down suddenly without any reason and programs are opening or closing automatically.

Missing Files and Programs

If you notice that programs on your computer do not work properly, which means some of your files are missing. Some virus causes problems by deleting files or may encrypt your files, so you aren’t able to open them. The files can be system files or files that you created, such as images or documents.

Missing files and programs is symptom of computer virus

If your computer missing system files and you are trying to use certain applications such as a browser or document editor, then those applications will refuse to run properly.

In that case, shows pop up a warning for you that the “critical file is missing”.

System Crashing

When your computer crashes suddenly, you may notice it does not seem to run normally and you should check it. If your computer self-restart frequently, every few minutes then this symptom may indicate that your system is infected by a computer virus.

Expert Tips

If your computer crashes, the best solution is to call your IT support center.

Computer system may infected by a computer virus

Out of Storage Space

This is another symptom of computer viruses that can increase or decrease the hard drive storage and make your computer unusable. If your computer keeps saying your drive is in low storage space, you may be surprised is caused by a computer virus.

Sometimes you will get the ‘low disk space’ warning message and you didn’t download any large documents even though you have enough storage space.

Expert Tips

To recover disk space, you must remove malicious programs from your computer, install anti-virus software, and update your software.

Computer Malfunction

Computer viruses can do all kinds of unexpected activities such as corrupting or damaging data, destroying files, formatting hard drives, or making disks unreadable. There are different types of computer viruses and they will affect your computer slightly in different ways.

Computer malfunction, which is another sign of computer viruses. The following activities or malfunctions will ensure that your computer has been compromised by a virus:

  • Computer starts to open files on its own.
  • System sending emails without your knowledge.
  • Internet sessions open scattered on their own.

Blocked From Antivirus Sites

If your computer has been infected by computer viruses, then your computer may be prevented from accessing the antivirus websites. The malicious viruses can modify internet browser settings by adding a Proxy Server and you will be unable to visit any websites.

Other types of malicious viruses change the computer’s DNS settings or add various entries to your operating system’s host file. By changing these settings, computer viruses can cause redirect issues or block the Internet connection.

Blocked from Antivirus websites is a sign of viruses

Advertisements on Web Browser

If your web browser is being redirected to another unwanted website, or advertisements are popping up when you browse the internet, then your computer may be infected with a malicious program called adware.

Adware is a software program that is designed to display advertisements on your computer screen within a web browser which redirects you to an advertising website and collects your sensitive data.

Expert Tips

If you want to protect yourself from adware, here is the best helpful tips for you:

  • Avoid clicking on advertisements.
  • Keep updated operating system and all other software.
  • Use antivirus software and Firewall.
  • Adjust Your Browser Settings.

Files Turned into Shortcuts

A shortcut virus is a type of malware that hides all of your files, and folders, and then replaces all the files and folders with shortcuts that look the same. When you connect a USB drive to a malware-infected computer and transfer any file from the computer to a USB drive then it automatically infects USB drives and appears as a Shortcut.

This malware initially released online and spread from one computer to another and if you try to open any file then you will get an error message.

How Computer Virus Spread?

In above section, our cyber security expert discussed 10 symptoms of computer viruses, which may spread in different ways. If you know the symptoms and how they spread, then you can easily protect your computer from viruses. However, computer viruses can be spread in different ways such as:

  • Opening an email attachment.
  • Clicking on a malicious executable file.
  • Visiting an infected website.
  • Copying data from infected computers.
  • Infected removable storage devices, such as USB drives.

Learn more about how computer viruses Spread?

Learn more about the Prevention of Computer Virus Attacks.


Finally, viruses infect a vulnerable system, access admin control, and steal sensitive information about your organization. You should know the symptoms of computer viruses to protect yourself from viruses. We have discussed the most common 10 symptoms of computer viruses. Hope the article will be helpful for you!

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