How to Tell If Your Computer Has A Virus

Unknown error messages and system crashes making your life a misery?

Pop-ups erupting all over the place?

Or is your web browser loading like you’re on dial-up?

If you’re sitting around asking yourself: “Does my computer have a virus?” then you just might be on to something.

No computer is immune to malicious software (malware) or viruses.

That includes you, Mac owners.

The truth is that if your computer suddenly starts acting funny (like slow performance) it might have a virus.

This blog post covers the various types of computer viruses and how you can protect your PC against malware, hackers, and other cybersecurity threats.

What Is A Computer Virus?

Let’s start with the basics.

A computer virus is a self-replicating computer program that makes changes or modifications to existing programs by inserting its code into the host program or application.

Once inserted successfully, the computer or mobile device is now compromised.

Most viruses target Microsoft Windows and use deceptive tactics to slip past antivirus software.

Viruses themselves are created for a variety of reasons, including extorting cash, political messaging, economic sabotage, identity or financial theft.

Sometimes, it’s just kids (script kiddies) looking for a cheap thrill.

But malware and viruses are no joke.

In fact, they cause billions of dollars’ worth of economic damage every year due to stolen or corrupted data, system failures, and wasted IT resources.

Perhaps the costliest malware outbreak in the history of computer viruses is the infamous MyDoom virus, which caused $38 billion in damages since it was first located in the “wild” in January 2004.

What Types of Computer Viruses Are There?

Here’s a list of some of the most common types of computer viruses and a short explanation of how they work:

  • Boot Sector Virus: Infects the master boot record
  • Direct Action Virus: Attaches to a type of file (usually COM or EXE) before spreading to other files in the directory once launched.
  • Resident Virus: A file infector that installs itself on a computer and can attach to antivirus software.
  • Polymorphic Virus: A virus that changes its signature with every replication, making it difficult to detect
  • Overwrite Virus: A virus that deletes the contents of any file that it infects

Common examples of computer viruses include CryptoLocker, which is an infamous form of ransomware that demands money in exchange for a decryption key,

Another is Storm Worm, which is a Trojan horse that infected thousands of computers back in 2007.

Warning Signs Your Computer Has A Virus

Fortunately, there are clear, tell-tale signs that give away whether a computer has a virus.

If your computer is experiencing any combination of the warning signs listed below, then your PC may be infected:

  • Your computer is suddenly running slowly
  • Your see a sudden increase in pop-ups and ads
  • Program and operating system crashes
  • Your contacts have received weird messages from you
  • Unfamiliar error messages appear
  • New icons or toolbars installed

Now that you know what to look for it, let’s take a look at how to identify the exact virus you’re dealing with.

And most importantly how to remove it from your computer.

Investigate the Causes

So, what can you do about malware after you’ve been infected?

First, run some diagnostic tests to determine what’s going on.

Check the Cause of The Slowdown

More often than not, significant performance drop-offs are the result of running out of RAM.

Use Windows Task Manager to view the Memory column under the “Processes” tab.


Here you can view which programs are using up your system’s memory.

Alternatively, it could be that there’s no storage space left on your hard drive disk (HDD).

Under the “Disk” section, you shouldn’t see any numbers exceeding 50-60 percent. If you do, it can be a telltale sign that rogue programs are running in the background.

Upgrading to a faster or bigger hard drive won’t fix the problem, by the way.

Check Your Browser

In ‘Task Manager’, check your web browser and see how it’s affecting your CPU and memory.

If it’s eating up a whole pile of your system resources (RAM and CPU) then that’s a sign something is wrong.

So you can start by getting rid of unnecessary and outdated browser add-ons or Chrome extensions.

If you don’t want to ditch extensions that you use every day, try temporarily disabling them.

Other things to watch out for are:

1. Your browser now automatically opens on a new homepage…and you can’t change it back.

2. You start seeing warnings that your “default browser settings have changed.

Either of these is a very strong hint that you have a virus or malware sneaking around inside your PC.

Run A Security Audit

There are plenty of freeware antivirus software programs to help safeguard your PC against the threat of malware and hackers.

Or to clean it up if it’s already infected.

If you want to find out how to prevent computer viruses from taking hold of your computer, your first step is to run a scan to detect any existing viruses.

Once detected, your antivirus software will give you the option of either cleaning, quarantining or deleting the infected files.

  • If it’s some random download you don’t care about then delete it.
  • If it’s a file you’re not certain about then quarantine it.

And if it’s a file you really need, well let’s hope that your antivirus software can clean it.

Upgrade Your PC Security

Once your antivirus software has detected any existing viruses and removed them from your system, start thinking about how to proactively protect your computer against future infections.

You can do this by making sure your antivirus software is up to date, and then make sure it’s set to update automatically.

While you’re at it, make sure there are now outstanding updates for your operating system or web browsers.

Most viruses exploit Windows computers that haven’t been patched against known security holes in them.

As a rule, take a more proactive role in your cybersecurity by using pop-up blockers, regularly changing your login passwords, and only download files from trusted sources.

You can also choose to upgrade from using free antivirus software to a paid option – there’s a reason why the paid option costs money.
The Bottom Line
The sad part of all of this is that people wait until they wind up with a computer virus before they take action.

I’ve seen this happen with personal friends and in big businesses.

The key is buy a brand-name antivirus package and keep it updated.

Don’t download files from sources you don’t recognize, especially files that end with .exe.

Hackers can only exploit vulnerabilities that you leave open to them.

So you can protect yourself from 99% of these problems by simply installing a good antivirus package that includes malware protection.