Is my computer safe from hackers?

Episode 1285 (11:53)

Kevin from California

Kevin's mom went to a website and got a virus alert. She then called the phone number on it and they had her install something, which gave them control over her computer. Leo says that's a common scam. They probably installed a virus and maybe even turned her computer into a bot. The worst part is that they took her money and now have her credit card number. She realized her error and called him, though, and Kevin has since changed her passwords. She has trouble remembering passwords. Leo says many do and they end up using the same password over and over. That's why a password vault is a good idea.

Should he erase the hard drive? Leo says no. She has a Mac and it's very secure. He's right to be concerned, and he should make sure the firewall is turned on to guard the network against a worm.