Author: Trey Williams
Tuesday, October 1, 2019

How Do I Know If I Have a Virus on My Laptop or Desktop Computer

Category: Security

Making sure you have up-to-date anti-virus software installed is the easiest way of protecting your computer against viruses. This software is usually the first to notice that something is wrong. But with malware and hackers getting ever more sophisticated, there will inevitably be times when your anti-virus software or firewall fails to spot something nasty trying to get into your system. With this in mind, we’ve listed some of the symptoms of a virus-infected computer below to help you spot when something has gone wrong. As with most things in life, the quicker you identify the problem, the easier it is to put it right.
How Do I Know If I Have a Virus on My Laptop or Desktop Computer
The advice in this article deals specifically with computers running Windows 7, 8, and 10.

What Is A Virus?

A computer virus is a type of malicious software (or malware). Malware is the name given to any kind of software specifically designed to disrupt or cause damage to a computer system without the user’s knowledge or permission. Different types of malware serve different purposes and have different symptoms and effects, but none of them have good intentions!

Specifically, a virus is a (usually) small program that, having been run once, has the power to replicate and insert itself into other parts of your computer at will. As a result, it can make unauthorized changes to files, programs and even control your OS (Operating System).

How Do You Spot A Virus?

The symptoms of a virus will depend very much on what that virus has been designed to do, but there are also certain things to look out for that are typical of this type of malware.

  • Noticeably slower or poorer performance: A slow computer doesn’t always mean that you’ve been infected with a virus, but if you notice a definite drop in performance or a sudden decline in boot-up speed, it’s worth investigating. The same applies if you’re experiencing lagging or freezing programs, full system crashes, or odd-looking error messages.
  • Browser re-directions and unknown extensions: A surprising new homepage that you didn’t set or extensions installed on your browser that you don’t recognize are two classic symptoms of infection. Similarly, if you used to browse at high speed and it’s now slow and sluggish, or you’re constantly being redirected against your will: something is wrong.
  • Pop-ups: A never-ending stream of pop-up windows used to be the heart-sinking hallmark of a virus successfully installing itself on your computer. Situations like this are less common now, thanks to increased ad blockers and better website security. However, if you do encounter this, be prepared to take immediate action.
  • Excessive hard drive or network activity: If you suddenly run out of space on your hard drive despite not installing anything new, or you notice giant spikes in the amount of data on your network connection, even when you’re not using the internet, you might be infected with a virus. This one is difficult to spot if you’re not generally aware of your average usage, but if your fan is regularly running even when you’re not working the computer very hard, this is a good clue.
  • Friends and family report strange emails and/or posts on social media from you: Viruses might hijack your email and social media accounts to try and gain access to your contacts and their computers. You might not realize this is happening until somebody mentions getting messages or emails from you that you didn’t send, often with a link or an attachment for the recipient to open. Change your passwords immediately and let everybody know not to open any correspondence from you that might be suspicious. Similarly, never click a link or open an attachment from anybody unless you trust the source.
  • You’ve been locked out of your computer: Ransomware is a type of malware that encrypts the information on your computer and prevents you from closing the window or opening any other programs. These viruses are normally accompanied by a demand for payment - a ransom - in exchange for restoring your access. Alternatives might include emails or messages demanding payment to stop sharing “incriminating data” or bank details. If you can access your computer’s Safe Mode, you may be able to remove the virus by restoring the system to an earlier date, but this isn’t always possible. In this case, we recommended seeking professional assistance.
  • No noticeable changes: Unfortunately, not all viruses are going to leave an obvious calling card for you to spot as soon as they arrive. Indeed, some viruses will leave minimal trace of their existence, causing no performance issues or noticeable changes.

What to Do If You Think You Have A Virus

Microsoft Defender is the anti-virus software built into the Windows OS, and this should be your first stop if you think you have a virus. Depending on the version of Windows you’re running, it may have been renamed Windows Defender Antivirus. Locate it quickly and easily by using the Windows Search Bar.

If you don’t have anti-virus software already installed, many of the top reputable brands will offer you a free trial for a limited period, and there are even completely free options that will provide a decent level of protection.

The anti-virus software will scan your whole system to (hopefully) find all the replicas and versions of the virus. It’ll then quarantine the malicious software and ask whether you want to delete or clean the infected files. You do.

How Do I Protect Against Further Viruses?

The best way to protect against further viruses is to keep your anti-virus software as up-to-date as possible and scan your computer regularly. Most anti-virus programs will have an option to check for updates and scan automatically or at specified intervals. If you get a notification that a new version is available, we recommend that you download and install this at your earliest opportunity.

You might also want to install a firewall, which monitors the information being transferred to and from your computer and contains additional tools for spotting and eliminating specific types of malware.


Viruses come in all shapes and sizes and can cause a wide range of problems. Keep an eye out for the obvious symptoms of a virus replicating across your system. These might include pop-ups, sudden drops in overall performance, suspicious network activity, and unwanted browser redirections. Not all viruses announce their arrival with fanfare. The best way to defend against infection is by keeping your anti-virus software and firewall up to date while running consistent scans of your whole system. Never open links or attachments from an unknown sender.

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