I use MalwareBytes. Microsoft tech support installed it a couple of years ago during a trouble shoot/tech support call. The Full version installs for a one or two week trial, then it reverts to the free version if you don't ante up. However, every couple of months a complete upgrade happens and then the Free trial starts again.
As for AVG, I used it for years until about a month ago when a trial version of something was holding me hostage and would not allow me to revert to the free version, so Hosta La Viesta.