If your computer is already infected with malware, see our related topic Remove Malware for Free .
There are several antivirus vendors that offer excellent free versions of their products for computers running Microsoft Windows. While you may assume the paid versions offer vastly better protection, that is not typically the case. The paid versions always offer some additional features, but the antivirus protection is usually very similar. If you do not currently use antivirus software, you should definitely install a free version. Or if you are burned out on the performance or annual renewal fees for paid antivirus software, you should consider a free version. Once you have had excellent results with a particular free version, you may want to support that product by upgrading to their paid version.
You can assess the effectiveness of free and paid antivirus software products by reviewing the test reports at AV-Test.org. Often the exact free editions are tested but sometimes only the comparable paid versions are tested. These products also include antispyware protection.
When installing any free software, be alert to uncheck the boxes for browser toolbars or other included add-ons that may add more clutter than value.
Effective and free Windows antivirus products tested at AV-Test Institute:
- Microsoft Security Essentials – Microsoft even allows use on up to ten computers at a small business.
- Panda Cloud Antivirus Free Edition – Our top pick for the best overall combination of protection, least number of false positives, least intrusive updates, least slowdown of your PC and least number of pop-up messages. Click the Options button during installation to avoid installing the additional browser toolbar.
Free versions not tested at AV-Test: Lavasoft AdAware Free and Comodo.
No free or paid product can provide 100% protection from malicious software.
When downloading a free version make sure you select the proper download button so you don’t end up with a 30-day trial instead. Do not select a ‘trial’ version if you intend to download a free version.
These products all have online support forums where you can get answers if you need help installing the software. Uninstall your old antivirus product first.
Sometimes you may need to download one of these uninstall tools for your current antivirus in order to install any free (or different) version.
If you have Vista or Windows 7, make sure you have turned off Microsoft Windows Defender. You can find it in Control Panel in Windows 7 or from the Start button then All Programs in Vista. If you leave Windows Defender running along with any antivirus program, your computer will run much slower. Usually, the antivirus program installation process will automatically turn off Windows Defender. (In 2012, Microsoft may release their next operating system called Windows 8. Windows 8 will include a free, updated version of Windows Defender that may finally be good enough for users to avoid using 3rd party antivirus software.)
So why do these companies offer free versions? Because they hope you will eventually upgrade to a paid version. And they sometimes include other options they get paid for like switching your default search provider to Yahoo or Google or installing an additional browser toolbar unless you uncheck these options during installation.
Antivirus product reviews and ratings websites:
PC Magazine – Various antivirus product reviews by editor Neil Rubenking. Neil publishes updated reviews and security news during the year.
AV-Test – New ratings summary posted every 2-3 months. Click on a product line item for a further details on how that product was rated.
Virus Bulletin – Click two times on their RAP Averages chart to zoom in and see the data better.