What happens is you get a phone call from someone pretending to be from Microsoft. They’re not. They’ll often be quite officious or even aggressive.
There’s different varieties of the scam. Some will ask you to check if a particular file is on your computer. When you discover it is they’ll ask for your credit card details to solve the problem. Of course, the file they’ve directed you to is one that should be there.
Other scammers will direct you to a webpage that will infect your computer. Some will ask you to download software or even to give them remote control of your computer. The outcome is the same. You’ve massively compromised the security of your computer and personal details.
A disaster.
Fortunately, it’s a problem that’s easy to avoid. The scammers have just got your name and number form a database. All they’re doing is calling people until they get some poor soul who’s taken in. So the answer is just hang up. Straight away. Don’t bother being polite. Don’t even bother being rude. Hang up and get on with your day.
And there’s one last thing you can do. Tell your friends and family about it as the scam relies on people being taken in. The more people know about it the less effective it is.