ok. now that you've gotten all the "educated" responses from all the technically advanced people on this site, I'm gonna suggest the simple approach. mind you this is all in good jest. but whenever my sister does something like this, i just give her a good smack on the back of the head and say, "why are you downloading crap like this?!?!?"

it might sound simple, but it works. she has absolutely NO inclination to learn about various issues/concerns/problems with what she does online. no matter how many times i try to explain it to her, she just doesn't care, doesn't want to learn, and doesn't listen. SO, i go for the smack on the back of her head whenever i catch her doing stuff like that. surprisingly, this works for her