Free software sometimes is really dangerous and I recommend to install trusted antivirus. Antivirus can protect not only your PC or mobile phone but all your information as well. antivirus-review.com is a place where you can found all information about antiviruses what you need. After reading some articles and some reviews on this site you will know more about viruses and how to protect your gadgets.
Moreover, a very important thing is antivirus comparison.
A virus is a piece of code that is capable of replicating itself in order to cause damage to your computer, including damage to your system or destruction of data. There is a lot of research on "antivirus vs malware"