Lisa went to a website and she got a pop up notification that her computer was infected and to call an 800 number to Microsoft. Leo says not to ever call them -- just exit the popup and move on. It's not infected and those popups are designed to insnare users. It's called a phishing scam. Lisa did it anyway, though, and gave them control of a computer. Leo says that's bad news because she doesn't really know what the hacker's done. He can install viruses on her or turn it into a bot, a keystroke logger, and use remote access to turn on her camera. At this point, the only thing she can do is backup her data, wipe the hard drive, and reinstall Windows from a known, good source.