6 Best antivirus for old computers [Lightweight Protection]

Ivan Jenic
by Ivan Jenic
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  • Older computers don't always have the latest software installed. This means that using an antivirus is crucial. However, some of them hog all the resources available. 
  • We have made a compilation of lightweight antiviruses. They should be light enough on the system so you won't know they are running.
  • If the computer is running slower than normal, see our recommended optimization tools and guides to improve the performance.
  • Protecting your digital assets is critical. Use the Antivirus Hub to find the right tool. 
lightweigh antivirus protection for old pc
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Do you want an antivirus for your old PC? Well, today we will be discussing the best antivirus for old PCs.

Antivirus software has become vital in this age of web surfing as computers need protection from Internet-based malware and other offline threats. This can pose problems with PC users of older Windows OS such as Windows Vista, Windows XP, Windows 2000, Windows NT, etc.

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Although the obvious choice should be to replace such PCs, sometimes people get attached to them more closely than other devices with years of data stored. So they keep their old PCs and continue using it.

However, most of the latest editions of popular antivirus may not run properly due to the PC outdated specs. Meanwhile, we have compiled some of the best antiviruses that run efficiently on older PCs with a focus on their functionality and effectiveness.

Best antivirus for old computers

BullGuard (recommended)

Bullguard for old PC

Independent tests have shown that BullGuard is capable of detecting a wide variety of malware.

The antivirus relies on virus signatures to detect existing known threats. It also provides behavior analysis that manages to block any suspicious activity from the software running on your computer.

This is part of their multi-layered protection approach. Other layers include a spam filter, backup capabilities, and more.

More proof that Bullguard cares about performance is the addition of Game Booster – an award-winning tool that blocks interruptions. While you might not be using your computer to play games, it just goes to show that BullGuard is the right choice.

With a clean design, it’s very easy to use and lightweight enough. It requires a minimum of only 1GB RAM and is compatible with Windows 7, 8, 8.1 and Windows 10.

BullGuard Antivirus

BullGuard Antivirus

Top antivirus that offers lightweight protection. Perfect fit for old PCs
$29.99/year Get it now

⇒ Read our full BullGuard review to learn more


Avast Antivirus

two-way firewall avast

Avast Antivirus is a worldwide giant in the antivirus industry with hundreds of millions of users worldwide. If you want an efficient antivirus for your old PC, look no further with Avast Antivirus. Moreover, it is compatible with all Windows OS.

This tool comes with features such as file scanner, Windows Explorer context menu integration, Rescue Disk, password manager, junk file cleaner, Wi-Fi inspector, Game Mode, and browser cleaner. In addition, Avast Free Antivirus comes with web, behavior, and mail shields.

You can download Avast Antivirus software from the tool’s official webpage.

Avast Antivirus

Avast Antivirus

Strong protection against all internet threats for your device
$55.99/year Buy now

Kaspersky Free Antivirus

two-way firewall Kaspersky

Kaspersky Antivirus is one of the widely used antivirus software in the world which gives protection against malware. The Antivirus uses a layered defense posture to scan your system quickly without giving false positives. It is also compatible with older versions of Windows OS including Windows XP and Vista which makes it a good choice for users with older PCs.

Some of the features of this program include file scanner, software uninstaller, gamers’ mode, ransomware decrypter, system restore, virtual keyboard, cloud protection, browser configuration, rescue disk, etc.

In addition, one of the unique features of Kaspersky is that it requires 512mb Ram and 480mb disk space to run; this makes it a great option for older PCs especially PCs which have 1GB Ram and slower processors.

Kaspersky Antivirus

Kaspersky Antivirus

Award-winning security from a well-known provider in the security field for over 20 years.
$39.99/year Buy now

360 Total Security

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antivirus for old pcThis software is efficient especially on old PCs so as to give protection against viruses, malware and Trojans. 360 Total Security has a unique advantage of being compatible with all versions of Windows from Windows XP to Windows 10.

This program offers three major protection features which include Internet browsing, Privacy, and System Protection. This makes it an attractive security tool for older PCs as it would install properly while giving premium functionality and protection.

However, this antivirus utilizes a lot of PC resources, especially when conducting full scans and trying to do other things with the PC. There is a distinct reduction in system performance for laptops not having more than 1.5 GB of free memory.

Download 360 Total Security from the official website.

Ultimate in Virus detection
360 Total Security website logo
  •  Frees your disk space 
  • WiFi Security Check
  • Latest patches and security updates available



antivirus for old pcThis is a web-based antivirus program that combines major antivirus programs together. SecureAPlus is ideal antivirus software for users of old PCs that can decide on an antivirus; in addition, it gives access to multiple antivirus engines. As it is mostly cloud-based it does not put much stress on your computer’s resources.

SecureAplus gives you the opportunity to test several products before deciding which one fits your priorities with features such as real-time protection, detection ratio, firewall, anti-phishing, scan speed, and resource consumption.

However, SecureAPlus is cloud-based and integrates 12 popular antivirus engines into one with a customizable interface for trusted programs. The antivirus engines include AVG, Avira, BitDefender, ClamWin, ESET, Emsisoft, McAfee, Microsoft Security Essentials, Norman, Quick Heal, Sophos, and Total Defense.

For more information, visit SecureAPlu’s official website.

Webroot Secure Anywhere antivirus


antivirus for old pcLast but not the least; Webroot Secure Anywhere is a web-based antivirus for your old PC. This antivirus incorporates premium security features in a tiny little package; hence, little computer resources are utilized while providing excellent protection to your old computer.

Webroot Secure Anywhere is a unique Security software that integrates firewall, web filtering, and Internet security into one package. The activation adds a password manager as well. In addition, this tool has very good detection rates for malware and virus threats with anti-phishing features.

Download Webroot from the official website.

Antivirus for PC Gaming
webroot official website logo
  • Full virus protection without impact on speed
  • Gameplay performance
  • Webcam protection

Do share with us your experience in using any of the antiviruses for old PC which we mentioned above. We do appreciate your feedback when you comment below.

Please keep in mind that these tools are also recommended for the following use cases:

  • antivirus for very old PC – Some of the tools have such low system requirements, that they qualify as very old computers.
  • best antivirus for old slow XP PC – Some really old PCs keep using Windows XP. While the OS is not recommended, take a look at antivirus for Windows XP.
  • best free antivirus for old laptop – Some of the solutions presented also offer a free version that has limited functionality. You could use that before upgrading to the premium edition.

FAQ: Learn more about antivirus for old PCs

  • When I install new antivirus do I remove the old one first?

A computer should not have multiple antiviruses software running simultaneously. Remove the current antivirus first, and turn on the new one. Use a third-party uninstaller in case of issues.

  • Does antivirus slow down PC?

Any piece of software that runs continuously will slow down the PC a bit. By how much? It really depends on the software. Some solutions are more lightweight than others. Check our top lightweight protection tools.

  • How many antivirus programs should be installed on a system?

Only one antivirus should be up and running. This is true for any computer, new or old. One good antivirus is enough to get the job done.

Editor’s Note: This post was originally published in February 2018 and has been since revamped and updated in June 2020 for freshness, accuracy, and comprehensiveness.

Editor's Note: This article was originally published in February 2018 and was revamped and updated in October 2020 for freshness, accuracy, and comprehensiveness.
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