We all know that the best way to avoid viruses is using common sense (avoid downloading suspicious files, not clicking in links from people that you don't know, etc), but using an antivirus is still recommended, even if you browse carefully.
Check below a list with the top 5 best free antivirus for download
5 - Spyware Terminator 2015
One of the most renowned anti-spyware software, now with a complete interface make-over exclusive to the new 2015 version. Over 30 million downloads are more than enough to prove the program's efficiency. With frequent updates and a huge database of viruses, definitely a must have if you care about your PC's health.
4 - Microsoft Security Essentials
A huge success since it's release, Microsoft's antivirus offers excellent real time protection with lightweight requirements. Microsoft Security Essentials is super recommended for users with older computers, since it has most of it's rivals features but uses 60% less resources.
3 - Avira AntiVir Personal Edition
A heavy contender to the number one spot, Avira has an amazing update rate, a huge database, numerous advanced features that allow deep customization, and a great browser bar that makes you safe even in the most shady websites. Even though it lacks a bit in the aesthetic part, it is one of the most powerful antiviruses in this article and is mainly recommended for advanced users.
2 - AVG Anti-Virus Free 2015
Top one for tech-illiterates, AVG is amazing for users that don't really know what they are doing when it comes to technology and computers overall, you only have to install it and the rest is totally automatic. It also presents an amazing interface and all the features that a top notch antivirus has, like real time protection, firewall, constant updates and browser safety measures.
1 - Avast! Free Antivirus 2015
The most famous antivirus software in the world takes the first spot in the rank. The clean interface and amazing features (for a free version), that none of it's contenders has, is surely a deal breaker.
Avast! is year after year the most downloaded antivirus in the world and it's quality can't be denied.