These are the top 5 best free antivirus software that you can use with your computer. They are also great for security against malware, spyware and adware. This antivirus software works on Windows and Mac computers.
Panda Free Antivirus: http://www.pandasecurity.com/usa/homeusers/solutions/free-antivirus/
AVG Antivirus Free: http://www.avg.com/us-en/free-antivirus-download
Bitdefender Antivirus Free Edition: https://www.bitdefender.com/solutions/free.html
Avast Free Antivirus: https://www.avast.com/en-us/free-antivirus-download
Avira Free Antivirus: https://www.avira.com/