What is a computer virus

A computer virus is a program or piece of code that is loaded onto your computer without your knowledge or permission. Some viruses are merely annoying, but most viruses are destructive and designed to infect and gain control over vulnerable systems. A virus can spread across computers and networks by making copies of itself, just like a biological virus passes from one person to another.

Computer Virus
Where a PC virus comes from

Computer viruses are usually hidden in a commonly used program, such as a game or PDF viewer, or you may receive an infected file attached to an email or from another file you downloaded from the Internet. As soon as you interact with the file (run the program, click on an attachment or open the file), the virus runs automatically. The code can then copy itself to other files and make changes on your computer.

How to recognize a computer virus

Your Internet connection might be slow or non-existent. It's common for your antivirus and/or firewall protection to disappear or be disabled. Computers infected by viruses are even capable of acting on their own, executing actions without you knowing. The best way to identify if you have been infected is to use a virus scanner, found in any virus remover software.

How to remove a virus

Remove all temporary files and run a virus scan using antivirus software. If any viruses are detected, delete them. Avast Free Antivirus includes a virus scanner and cleaner, which can easily and quickly remove any virus from your device. But it’s more than just a free virus removal tool - it’s also real-time protection against all virus attacks.

How to prevent viruses
  • Avoid programs from unknown sources.
  • Don't open attachments from unsolicited email or in Facebook.
  • Only download apps from Google’s official Android Market.
  • Secure your phone with Avast Free Mobile Security.
  • Regularly scan your devices with a virus scanner, and remove all detected viruses using virus removal software.
Use a free virus removal tool to protect yourself

There is no better way to recognize, remove and prevent viruses than to use an antivirus tool with a virus scanner and cleaner, the best of which is provided for free by Avast.

Why Avast?
  • Consistently rated “excellent” by industry experts
  • Trusted by 400 million people worldwide
  • It’s the "Antivirus with the lowest impact on PC performance” (AV comparatives)
  • Best features - unbreakable password security, home network protection, browser cleaning and much more
  • All for FREE
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