Though I personally feel that it would take a very gullible individual to fall for this, it appears that the presence of continuing pitfalls in the form of computer repair scams are pervasive; likely due to a lack of sophistication of the typical computer user.
Recently my elderly aunt received a cell phone call from "microsoft" saying that her machine was compromised and required immediate attention by their skilled technicians to forestall total calamity. The insinuation was imminent failure with total loss of her machine and it's content.
It was a ruse which worked to their advantage and unfortunately she suffered financial predation by these individuals to the tune of five hundred smackers.
She lacked experience with this type of low down shyster causing undue separation of cash from her payment card but at least she has not engaged them further.
It would not surprise me if microsoft held specific scammer classes in their scam called "certification training" because that's a big chunk of their revenue as well. Creating software so easily exploited is the hallmark of an over commercialized underthought technology.
Our informational footprint — that stuff you put out there provides more the scammers have with which to "get you".
Back up your data, preferably on a removable medium like a USB 3.0 drive or some flash memory component.
If approached in a "cold call" whereby you did not initiate the interaction you should hang up immediately. Nobody out there ... especially a scammer is so benevolent as to volunteer such repair service in the nick of time as claimed by these idiots who would have their way with you.
Watch those mouse clicks when encountering any web page. It's far too easy to click a redirected link and end up with a cryptolocker exploit ... particularly if you haven't maintained an external backup like you should as a matter of routine.
If you need support, get someone you trust even in the presence of computer services that are largely inflated on the cost side. Expect to drop some cash; often more than you might expect.
Acquire knowledge of simple maintenance procedures and exploit preventive measures. They will go along way to keep yu safer over time. I recommend the malwarebytes software and personal firewalls available for free. Just be sure of the download source ... they too can be problematic.