Keep in mind this system belongs to an "end user". End users usually don't have the same technical aptitude as we do. We know better than to stick our necks out surfing. But if we choose to we know how to protect ourselves. And if we get slapped with something, we know how to clear it out. That's the difference between us and the accursed "end user". No offence "end users", but it is what it is.
In this case the person is brilliant when it comes to remodeling hotels and office buildings but is somewhat less than stellar when it comes to computers. They know I'm good with computers and my flying models so they come to me.
As for running bareback with just windows defender, you have got to be kidding. Windows defender is a joke. It misses more than it catches.
I tried it for a while but when I had to resort to reinstalling the OS twice I got NOD32 then updated to the suite and have been using that for years. Very happy with it. Well worth the expense. But not every one knows how to get it, install it, and run it on a regular bases. And not every one wants to spend money on anti virus protection.
I had to do something and it was either AVG or Avast. I went with AVG. If it was my machine you bet your bippy it would have ESET on it.