I was setting up my new-to-me laptop and needed a solitaire game that DH likes. Keeping this in mind, I was very careful when downloading it (It did go thru CNET) and I hit "Decline" for everything except the game , I thought.
Something called "Lucky Leap" got on there anyway! I had to remove it. Very annoying.
Run something like Malwarebytes regularly and esp., after you download something.