Anti Virus Free from AVG is one of the best free antivirus software tools available and is probably my personal favorite.
Overall, Badiu Antivirus 2015 ran quickly, using little system resources, and functioned just as good as the other antivirus programs in this list.
Baidu Antivirus 2015 works in Windows 10, Windows 8, Windows 7, Windows Vista, and Windows XP.
See my Free On-Demand Virus Scanners list if you're interested in free antivirus tools Lavasoft's Adaware Antivirus Free program is different than the "Ad-Aware" you may already be familiar with.
This program is a true, always-on, completely free antivirus program.
Though it's not officially compatible, it may also run just fine on Windows 10.
Baidu Antivirus 2015 is lightweight and fights malware via its cloud-based virus database.
Avira Free Antivirus works on Windows 10, Windows 8, Windows 7, Windows Vista, and Windows XP.
Avira can also be used on a Mac and Linux computer.
The scope of malware that Avira Free Antivirus can keep you safe from is alone enough to make it one of the best free antivirus software programs but the heuristics and ease of use add to its value too.
The only things I didn't like about Avira Free Antivirus was the configuration you have to complete after installation which might be intimidating if you're a computer novice.
I also like the fact that AVAST has been making this antivirus product since 1988 and is often cited as the most installed antivirus product.avast!