What is a computer virus?

A virus is a harmful program created by hackers that can infect your computer or device in multiple ways. They can be incredibly difficult to get rid of and they can spread from device to device. Fortunately, there are steps you can take to protect your devices and we have some tips about how to remove a virus.

How does a computer virus work? A virus is written by programmers to attach, overwrite, or otherwise replace another program on your computer in order to reproduce itself without your knowledge.

A virus can cause a number of problems on your infected device. It may quickly use all your computer's available memory — slowing down your system or bringing it to a halt. Viruses can damage data, destroy files, format hard drives, or make disks unreadable. A virus can enter your computer as an email attachment, in a downloaded file, or hidden on a zip drive or CD. It's usually not obvious that a virus is present on a website, in an email or elsewhere.

Common computer virus symptoms

If you're experiencing any of these problems, your computer may have a virus:

  • Freezing and/or crashing
  • Missing or corrupt files
  • Difficulty saving files
  • Computer unexpectedly restarts
  • Programs randomly open
  • Task manager won't open
  • Constant pop-up boxes
  • Much more spam than usual in email
  • Windows updates don't install
  • Unable to open files and folders
  • Passwords have been changed
  • Problem installing new software
  • Noticeably slower on startup and/or shutdown
  • Unexpected errors such as low memory, system files missing
  • Hardware issues such as nonresponsive keyboard, printer

How do I avoid getting a computer virus?

There are some precautions you can take to keep your devices safe:

  • Install a reputable antivirus program. Even if you don’t take any other preventative measures, using antivirus software will provide your devices with basic virus protection and monitoring. This ensures that if you do get infected, you will be notified quickly and you can address the issue before the virus has a chance to do irreparable damage to your computer. All CenturyLink High Speed Internet customers can download McAfee antivirus software at no additional charge. Learn more about McAfee
  • Keep your virus definitions up to date. To be effective, antivirus software must be kept current. It's important to download the latest virus definitions when your antivirus software tells you to. You can automate this task so you don't forget to do it. McAfee security is cloud-based protection that offers continous updating and monitoring, so you don't need to think about updates.
  • Run your antivirus software routinely. Again, if this is something you find to be a pain (or you just forget to do it), you can automate the task.
  • Be proactive. Scan your files and programs. You can set up your antivirus software to automatically scan emails and files before you open/download them. It's wise to scan ALL files, even if you trust the source.
  • Back up your files regularly. New malware is created daily. Having a backup of your data can be a lifesaver if a virus gets past your protection measures.
  • Keep your operating system and programs updated. This may seem like a hassle, but updates are vital for keeping your computer virus free. Updates often include patches to security vulnerabilities that could be exploited, and if you don’t update, you may be missing out on the latest protection. You can also automate this task in your computer's settings.
  • Secure your WiFi network. Enabling a WPA password on your home WiFi will help to prevent unwanted users from getting on your wireless network. If you need to provide internet to friends, most routers allow you to set up a guest network that lets them use the internet without giving access to your primary network, protecting you from potentially infected devices. Select modems leased from CenturyLink also offer Secure WiFi, with security from McAfee built right in. 

How to remove a computer virus

If you think your device is infected, your first step is to run a complete scan using your antivirus program. 

If you are using CenturyLink Security by McAfee, there's no need to do anything extra. The program runs continuously and automatically quarantines any detected threats.

If your antivirus program is unable to remove the virus, these are your next steps:

  • Try an online search for virus removal. You're likely to get the most accurate results if you have a suspected name or source of the virus, or can describe the specific symptoms.
  • Call in a professional. If you subscribe to the CenturyLink @Ease® Ultra plan, you can have a CenturyLink tech help to remove viruses from your computer. Visit the CenturyLink @Ease page to learn more about this program and options. If you are not a subscriber to @Ease, you can find a local IT professional.
Types of computer viruses

Bug Icon - solid green

Now that you know what a computer virus is, you may be surprised to learn that there are many different types of computer viruses out there and each of them affect your machine differently. Below are a few of the different types of computer viruses that may infect your computer:

File infector virus

File infector viruses are some of the most common computer viruses. They infect executable files on your device, and once the file runs, the virus will rewrite the files’ code to perform an action which may or may not be malicious. These types of viruses can spread to other programs on your computer and should be removed as quickly as possible. 

Boot sector virus

Boot sector viruses are typically spread through physical means such as flash drives, but they can also be spread through email. They operate by infecting your computer's Master Boot Record and are only able to infect your machine if they are used to boot up your operating system. Luckily, these viruses are not as prevalent as they used to be, but because they can be extremely destructive and hard to remove, a preventative antivirus software is recommended to ensure your machine does not contract this virus. 

Browser hijacker

Browser hijackers take control of your web browser to spy on your browsing or to send you to sites you may not be trying to visit. The hacker does this to boost ad revenue for the site. Additionally, these viruses can steal any personal information you enter into a site if they are spying on you, so if your browser starts to exhibit strange behavior such as long load times or excessive pop-ups, we highly recommend you scan your device for viruses. They typically find their way to your computer through an infected browser extension and can be removed by running your antivirus software.

Polymorphic virus

Polymorphic computer viruses are some of the most complex viruses your computer can become infected with. As their name would imply, they are able to alter their code, making them hard to detect and remove. They are a form of an encrypted virus and use different encryption keys every time they change their underlying code. These types of computer viruses are spread through a wide variety of media including spam, infected files, or malware. A sophisticated antivirus software or IT professional are typically required to remove this type of virus.
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