Is there a good free antivirus program for Windows 8.1?

I need such a program for a friend with modest means who has an older PC that uses Windows 8.1.

Thanks,

Bob

Suggest you use Windows Defender which is included as part of the Win 8.1 operating system.  Be sure to uninstall whatever AV program is on the computer and use the appropriate software removal tool(s) to ensure that all remnants of previously installed AV programs are removed. List of antivirus product removal tools

Alternatively  - - - 

Recommend you review the following…

https://support.microsoft.com/en-us/help/18900/consumer-antivirus-software-providers-for-windows

Choosing an Anti-Virus Program

Regards…

http://blog.emsisoft.com/2015/01/27/top-10-ways-pups-sneak-onto-your-computer-and-how-to-avoid-them/

I need such a program for a friend with modest means who has an older PC that uses Windows 8.1.

Thanks,    abdu

Use the built-in Windows 8.1 Anti-virus Windows Defender.

But also use the free on-demand version of Malwarebytes anti-malware scanner as a supplement for extra protection.

The free version is an on-demand scanner, not a real time scanner, so won't cause conflicts with Windows Defender.

Scan with it once a week, depending on your web surfing habits.

http://www.malwarebytes.org/products/malwarebytes\_free

And disable the Premium Trial and set it to the permanently free on-demand version:

https://support.malwarebytes.com/docs/DOC-1033

I just wanted to add, for anybody who reads this post, that I disabled the Premium Trial as Bill recommended. But the instructions for deactivating the Premium Trial are a little different from the link in the quote above for the latest version of Malwarebytes (v4). The latest version deactivation instructions are here

https://support.malwarebytes.com/hc/en-us/articles/360040972954-Deactivate-Premium-Trial-in-Malwarebytes-for-Windows-v4

QUESTION: My friend has Windows 8.1,  I have Windows 10. Should I also download and install Malwarebytes (anti-malware scanner) and use it manually every week?

Thanks,

B.

Use the built-in Windows 8.1 Anti-virus Windows Defender.

But also use the free on-demand version of Malwarebytes anti-malware scanner as a supplement for extra protection.

The free version is an on-demand scanner, not a real time scanner, so won't cause conflicts with Windows Defender.

Scan with it once a week, depending on your web surfing habits.

http://www.malwarebytes.org/products/malwarebytes\_free

And disable the Premium Trial and set it to the permanently free on-demand version:

https://support.malwarebytes.com/docs/DOC-1033

Thanks for your response Le Boule and Bill. I appreciate them.

B.