What’s a pc virus? Learn how to spot and keep away from viruses
- A computer virus is a type of malware that can replicate on your computer and spread to other devices.
- You could be infected with a virus if your computer suddenly runs slower, crashes frequently, or runs unusual programs without your permission.
- Here is everything you need to know about viruses, including the main types, signs of infection, and how to avoid them.
- Check out the Business Insider Tech Reference library for more stories.
Now that PCs have been a part of everyday life for about 30 years, computer viruses are no longer as mysterious as they used to be. Simply put, a virus is a type of malware that can replicate itself. Once activated, it can install itself on one computer, infect the PC, and allow the virus to continue to spread to other computers.
Depending on its payload, the virus may have no other impact on PC other than copying itself, or it can be designed to cause a wide variety of damage – from keeping the files on the computer as a ransom (this is called a Ransomware) to deleting files, crippling Windows or turning the computer into a resource for hackers to carry out distributed denial-of-service (DDoS) attacks.
What you need to know about computer viruses
Viruses have been around for decades (the first virus was created in 1971) and are so synonymous with the concept of malware that some people refer to malware as a virus. That’s not really true – there are many types of malware, and viruses are just one.
Unlike other types of malware, a virus rests until activated – it cannot execute itself. (This is in contrast to a worm, which can run on its own, for example, without human intervention. This means that you might accidentally download a virus onto your PC, but it won’t run until you run the file or open the file Document in which it is embedded.
At this point the virus code is activated. He can execute his user data, e.g. For example, stealing passwords, sending e-mails to the contacts in your address book or taking over your PC in a ransom attack.
There are different types of viruses that you can get infected with. While this may seem unimportant – why should it matter since you are already infected – it is important to know that each virus can affect your PC differently. Here are the most common varieties:
- Boot sector virus: A boot sector virus can take complete control of your PC by infecting the part of the hard drive that contains startup instructions.
- Polymorphic Virus: This type of virus is particularly insidious because it can vary code and make it difficult for antivirus software to detect and remove. Modern antivirus software detects polymorphic viruses pretty well, but it is far from perfect.
- Web scripting virus: This virus specifically targets vulnerabilities in web browsers, but the virus doesn’t stay there – it can be designed to affect all aspects of your computer.
- Macro virus: Fortunately, macro viruses are less of a threat than they used to be. They are written in the “macro” language used to create scripts in programs such as Microsoft Word and Excel. When a document is run with an infected macro, it can do many harmful things to the PC.
- File Infector Virus: These viruses can inject malicious code into other programs and documents.
How to spot signs of a virus
The symptoms of a computer virus can vary dramatically because not all viruses are designed to do the same thing. However, if you are concerned about being infected with a virus, here are some things to keep in mind:
Your computer’s performance suddenly changed
If your PC is running much slower than it used to be, a virus can be using your PC’s resources.
Your computer crashes frequently
Many viruses are poorly written and can cause many unexpected crashes and failures.
Lots of popup windows
You may see unusual pop-up windows in your web browser or elsewhere. These can be requests to visit websites or your browser opens windows to other websites without your permission. Ironically, many viruses also open pop-up windows asking you to install antivirus software, which is additional malicious software.
New programs are running on your PC
Programs may appear that you cannot remember installing when you start Windows.
Your email account is sending unsolicited email to your contacts
This is a sign that the virus is trying to replicate itself through your contacts.
How to avoid viruses
The good news is that viruses represent a tiny shadow of the risk they once posed in the 1990s and 2000s. Thanks to the dramatic improvements Microsoft has made to Windows, large-scale virus infections are much less common than a decade or two ago, and few people ever encounter viruses while using computers for normal, routine tasks. Even so, it pays to be vigilant if you follow the tips below:
Keep your computer up to date
Make sure your computer’s operating system is up to date with the latest Windows and security updates.
Use anti-virus or malware software
This could include the security software built into Windows 10 or a third-party antivirus app. Whichever you choose, one of the main reasons people no longer have to worry about viruses today is that Windows and anti-malware software automatically protect them. Disable this protection and you will be back to 2005.
Don’t click any suspicious links or attachments
You’ve no doubt heard this advice before, but that’s because it’s so important: never click on something you don’t trust. This includes both links and attachments in emails – if you don’t know the sender or if the legitimacy of the email is questionable – don’t open anything in them. The same applies to following links on websites of questionable quality.