A new Windows Activation scam has been discovered by Malwarebytes security researcher Pieter Arntz. This particular infection will play an audio message every time you click on the screen that asks you to call the listed number for help. When I called the number, I was connected with someone who wanted to take control of my computer. After further discussions with the agent, I found out that these scumbags were charging $99.99 USD to “buy a product key”” and remove the message that is displayed.”
Source: https://www.bleepingcomputer.com/news/security/windows-activation-scam-locks-your-screen-and-doesnt-shut-up/