Matt's mom got bit by a remote access scam and he's gotta clean up her computer to make sure it's secure. Leo says it's a common scam designed to get one to launching the "event launcher" which will show "red x's", which Leo says are perfectly normal. But if she doesn't know that, it'll make her think there's something wrong with her computer. But there isn't. Then they'll try and get her to give them a credit card to pay to fix it remotely. That gives them her credit card. Once that's done, they'll tell her they need remote access. And once that happens, they can put malware on her system, including a keystroke logger.
So what Matt needs to do is assume that the computer is infected. Back up the data, format the hard drive, and reinstall Windows from a known good source. He can download the Windows 10 media creation tool directly from Microsoft. Then update it.
A better idea may be to get her a Chromebook instead.