If you are using Windows 10, you should consider that antiviruses are now useless, with W10 SmartScreen blocking everything new and Windows Defender doing the rest.
As a computing veteran (since the 80's), I no longer use third-party antiviruses even in Windows 7: only MS Security essentials, Clam AV on demand and strong ad blockers on Web browsers. I gave up antiviruses because they always block the innocuous apps I write myself, with proud warnings about discovering a highly dangerous file on your computer, but indeed they are never ready for the latest threats.
I met 2 serious viruses in all my computer life: MS Blaster in 2003 and, the worst, TDSS. Both came through my Internet connection, on Windows XP, with Avast (free edition) running and up to date. I managed to remove both of them by rebooting immediately on Linux, then examining all Windows system files. I always keep a copy of infected files: Avast was able to detect TDSS as a virus about two weeks later. No antivirus had heard about TDSS when I was infected with it. I also tried Kaspersky, which was not better, and often even more troublesome.
Antiviruses are only braggarts, boastful warriors who kill only wounded enemies. In more than 30 years, I NEVER saw an antivirus blocking a virus attack. They work only when you test them on known and already outdated viruses.