Tech support scam
I had a customer fall victim to the tech support scam via a fake Geek Squad invoice email. In a moment of inattention during a bad day, they called the number & let the scammer remote in despite it feeling wrong. They caught on & force-shutoff the PC before the scammer could completely retaliate, but he got far enough to install the PC lock-out program that would've effectively bricked their PC.
All it takes for anyone to fall victim is just one single moment of inattention.
Tech support scam
Anyway, the program was Lock My PC Free Edition. The scammer had set a passcode on the uninstaller, & he was about to set a passcode for preventing Windows from booting when the customer disconnected.
The passcode on the uninstaller means you can't uninstall it without that code.
The devs realized tech support scammers were its most eager users, so:
Bleeping Computer, 2020-02-08, "Lock My PC Used By Tech Support Scammers, Dev Offers Free Recovery": https://www.bleepingcomputer.com/news/security/lock-my-pc-used-by-tech-support-scammers-dev-offers-free-recovery/
Tech support scam
You know you done messed up when you have to provide the public with a cracker/keygen for your own product.
Anyway, something you might want to have squirreled away in case any of your less computer savvy friends & relatives don't realize it's a scam until after they invite the tech support con artist into their PC.