Causes and signs of virus infection

Causes and signs of virus infection

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In the process of using your computer, if you are not careful or have just one small mistake, your computer is very susceptible to virus infection.

So how do you know if your computer is infected with a virus or not and the cause. This article we will find understand more thoroughly about Viruses and how to avoid it.

How do I know if my computer is infected with a virus?

I. What is computer virus?

First, I will talk about the concept of virus, you can simply understand that a virus is a very small software and it has the ability to replicate and copy itself from one infected file to another. And of course there are many types of viruses from simple to complex, sometimes just a short piece of code, it is often created with malicious intent.

Viruses develop very strongly in the Windows operating system, not because the operating system is weak in security but because it is too popular, many “pros” look at and write down malware in order to deceive the user for his benefit.

II. Where does the virus infect?

Viruses can spread through computers from many different sources. It could be spread over the Internet, spread over LAN, spread from peripheral devices…. And I will list out some specific cases below:

  • Spread via USB, memory stick, CD drive, etc. or other removable devices. This is quite common (you should read the article on how to block viruses from spreading from usb).
  • Spread by email, email services or files downloaded on the internet.
  • Due to copying and using files that have been infected with viruses before.
  • Due to users visiting unhealthy websites.
  • By clicking on the links containing viruses on the internet, the virus files are attached to the image.
  • Use pirated, unlicensed software from unreliable sources, and do not test thoroughly before using.
  • Infections via LAN or intranet.
  • Virus infection due to software installed on the computer has security holes.

= >> Virus is getting smarter, or more accurately, the virus creator is getting better and more sophisticated, so the user will be more easily fooled.

III. How does virus work?

File infected with virus => after being activated (accidentally activated by the user) => starts to work and resides on the infected file => continue to find other objects to infect.

This process will repeat over and over until all files are infected if you don’t have any protection.

How does a computer get infected with a virus?
How are computers infected with viruses?

IV. Harmful when infected computer

Viruses cause a series of serious problems for us, they can slow down the computer, consume resources, damage Windows, lose data, steal data, blackmail users such as Ransomware WannaCry. .and many other harms that cause user inhibition.

V. What are the signs that a computer is infected with a virus?

  1. Computer starts up slowly, with freezing, jerky and lagging than usual.
  2. The computer automatically starts or shuts down for unknown reasons.
  3. The anti-virus software or the firewall was suddenly disabled and cannot be used.
  4. Cannot start programs or applications on your computer.
  5. The drive, folder cannot be used or the print job on the computer cannot be used.
  6. Desktop icons are lost or changed.
  7. Access, open files or open program files slowly.
  8. Strange files appear when opening the USB hard drive.
  9. Suddenly appeared files with an .exe extension with the same name as the folders.
  10. There is a yellow triangle warning in the right corner of the screen “Your computer is infected”, or a window of “Virus Alert” … appears.
  11. Appears website advertisements automatically appear (pop up).
  12. When you open the web browser, it automatically opens strange web page popup windows.
  13. The internet speed was very slow, although the network was normal.
  14. The desktop is changed even though you did nothing.
  15. Can not use system tools such as Task Manage or Registry Editor (Press Ctrl + Alt + Del to open Task Manager, CPU and RAM are always high, even 100%.)
  16. Many strange programs, software or tools run automatically upon startup.
  17. There are many strange icons that you have never installed.
  18. The web browser that you use all the time has its homepage changed automatically and cannot be reset.
  19. Folder Option function is locked.
  20. Folder icons return to the iconic form of ancient Windows XP 😀
  21. Strange toolbar appear on the web browser.
  22. Change browser navigation, for example, if you visit page, it turns out a completely strange page.
  23. Your computer loses control.

Note: Some types of Viruses, malware, trojans, spyware are even more dangerous, it is almost harmless to the computer and it tries to hide all its activities in order to evade the user’s detection.

But the dangerous thing is that it will quietly and silently steal your information through the remote control system. That is why you really need an anti-virus software to permanently protect your computer.

How to prevent computer viruses
How to prevent computer viruses

BECAUSE. How to prevent viruses for computers

There are some pretty effective methods to avoid Viruses that you should apply as follows. If you know it well, the risk of a computer being infected with a virus is very low.

  1. Avoid copying and using unknown programs, if possible, you should try and test on a virtual computer first.
  2. Do not download and use files from unknown email.
  3. While surfing the web, using the internet, you should not click on strange links, images with hidden links.
  4. Do not visit unhealthy, perverse websites.
  5. You should enable and use the Firewall in Windows.
  6. You should update the software you are using on your computer to the latest version because it is patches of the manufacturer to protect users. If you are using a genuine “Windows”, you should also update.
  7. Back up important data periodically in case the worst case occurs.
  8. If your file is <128MB, you can check if the file contains viruses through online tools. VirustotalYou can also scan the link (URL) if you are in doubt, this tool has integrated 57 reputable virus scanning software so it is very accurate.
  9. Use of anti-virus software: If possible, you should use copyrighted anti-virus software such as Kaspersky, bitdefender, NORTON â„¢ … or without, you can use one of the anti-virus software. free is also quite OK.
  10. Using my own experience in the process of using the computer and reinstalling windows is the last solution.
  11. And it’s important that you read this article again: 13 notes you MUST KNOW to stay safe on the internet

VII. What to do when the computer has a virus


  1. The first job and you also need to think about is the data. You should back up to another device what files and files you think are most important so that when a virus damages or erases your data, you have a different safe backup plan.
  2. Disconnect internet, LAN … quickly unplug the network. If you use Wifi, turn off the wifi.
  3. Install a virus scanner if you don’t have one, then scan the entire hard drive.
  4. Enter Safe mode or rescue CD / usb boot to reset or scan the system for viruses: If you cannot boot into Windows then go to Safe mode (see instructions on how to enter safemode) to prevent Block unnecessary startup components to prevent malware activities and remove malicious software.
  5. If you can’t boot into Safe mode, you can create a USB BOOT to scan and remove viruses. You should create a versatile bootable usb as in this article: Instructions to create a fully functional USB BOOT. Then use built-in anti-virus tools such as KAS Virus Remove, KAS TDSSkiller… to remove virus for the whole computer.
  6. Encourage you to consult and follow the instructions in the article: Speed ​​up your computer – 12 steps to have a computer like new
  7. Some computers are infected with malware and Adware adware, please refer to this tutorial, which is very effective: How to remove adware on web browsers, computers
  8. If still not feasible, you should reinstall the operating system.
  9. After the above work is completed, the last thing you need to do is change the passwords of previously logged-in accounts on the infected computer to avoid losing your account and information.

VIII. Epilogue

Above are experiences to avoid virus, signs identifying infected computers as well as the process of self-learning about Viruses from many sources that I want to share with you.

Although it is not 100% resistant to viruses, if you have the above experience, you can minimize the bad cases that can happen to your computer.

Hope the article will be useful to you and hope to contribute more tips, good experiences from readers.

Good luck!!!

Kien Nguyen – techtipsnreview

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Source: Causes and signs of virus infection
– TechtipsnReview

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