I’ve used quite a number of security software packages over the years, and with the recent difficulties I’ve had with commercial packages, I’ve switched on my home machines to Comodo Internet Security.
Comodo provides free antivirus protection, and free firewall and anti-malware.
I believe that Comodo is the best free antivirus for Windows, and you can download the internet security package for free at Comodo’s Website. When you go to this link, go to where it says “Internet Security” and “Free Download” underneath.
Comodo updates automatically in the background while you are connected to the internet, and once you have initially trained the firewall (as with any firewall program), it rarely gets in the way of your daily work.
I’ve found Comodo easy enough for novice users, yet customizable enough for more advanced users, as well.