Computer Viruses Explained


Computer viruses have been around almost as long as computers have. In this slide show we look at what our virus protection needs to combat.

What is a computer virus?

A computer virus is a piece of coding, sometimes as small as a line, or as large as an entire program that can copy itself. It either inserts itself into a file and hides there, or attaches itself to one and tags along to infect your computer. The more complex the virus is, the harder it is for antivirus software to protect against it.

How will you know if your computer has a virus?

Your computer might:

  • Respond and / or operate slowly – the extra work your computer is doing with the virus inside it could slow all processes.
  • Crash repeatedly – due to your computer being unable to cope with the extra processing, you could lose data and work during crashes and restarts.
  • Delete files without your permission – this might be part of the virus or it might be part of a combating system to try to delete the file with the virus in it.
  • Repeatedly open windows and ads – this is often a sign that something is malfunctioning. You’ll see repeats of one window opening and re-opening and taking over the screen.

How Many Different Viruses Are There?

Types of infections include:



Trojan horses


These are all common types of computer infiltrators. Previously, viruses would only perform one type of action. For example, you might just get a file infector virus, which would only infect one type of file in your computer. Or you might have a browser hijacker virus – this is one that takes over your browser windows and changes your searches. It also redirects you to its own virus page no matter what you type into your search engine.

But these are relatively simple and the way that viruses have developed means that they can now attack on multiple fronts. This makes it much harder to detect them, to fix the damage because it’s more extensive and to entirely rid your computer of them once they’re embedded.

A virus such as one known as Dexter infects your computer if it runs Microsoft Windows. It takes personal and confidential data and was only detected in January 2014 in online banking transactions. This is obviously a huge problem when it comes to identity and financial security, and means that anyone who has access to this virus could hack into your details.

A Worldwide Problem

At the 2015 World Economic Forum the tech conversation focused on how to react to viruses and hackings. The problems used to be about how to prevent viruses getting into systems, but now the big businesses understand that this is inevitable, and computer protection theory is as much about damage control now as it is about antivirus software.

How to Stay Safe

The most important thing when it comes to virus protection is to make sure your computer is equipped with antivirus software to ensure that you have high functioning computer protection.


Advertising Disclosure

This site is a free online resource that strives to offer helpful content and comparison features to its visitors. Please be advised that the operator of this site accepts advertising compensation from companies that appear on the site, and such compensation impacts the location and order in which the companies (and/or their products) are presented, and in some cases may also impact the rating that is assigned to them. To the extent that ratings appear on this site, such rating is determined by our subjective opinion and based on a methodology that aggregates our analysis of brand market share and reputation, each brand's conversion rates, compensation paid to us and general consumer interest. Company listings on this page DO NOT imply endorsement. We do not feature all providers on the market. Except as expressly set forth in our Terms of Use, all representations and warranties regarding the information presented on this page are disclaimed. The information, including pricing, which appears on this site is subject to change at any time.

Top 5 Antivirus Software Sites