If your looking for free software, there are a lot of options and combinations you can do with your computer security.
For my computer, I use Avast for real-time protection and I use MalwareBytes for on-demand protection.
For privacy and optimization, I use CCleaner and Cyberghost/Hotspot Shield, PrivateFirewall, and Snadboxie when needed.
You can also install extensions for your browser such as Https everywhere, and adguard.