Frank got fooled by a Phishing popup. He called the 800 number that was associated with it and they charged him $300 to "fix it." Leo says they were pretending to be Apple Care. It's a scam. Frank suspected chicanery and called Apple Care, who confirmed it was a scam. Leo says that's a smart thing. So he turned off the computer. He doesn't see anything wrong with his computer, but what should he do? Leo says that chances are they probably didn't get far, so Frank is probably OK. But just in case, he should get a program called Little Snitch. It'll watch outbound traffic to see if they put anything on it.