I don't have a virus scanner. I turn off Windows defender right after I install (along with windows firewall). I don't install much on my PCs, just textpad (I own a license), vcl, google chrome, and mingw on dev machines or utorrent (downloading mp4 movies) on my htpc.
I also re-install about a year or every other year. I've had these problems constantly on a lot of machines, and most of the people at my work who I've discussed this with have similar experiences.
I guess I could screen record some videos on a few different machines if people don't believe me.