There's a scam going around that has Microsoft & Apple customers reaching into their wallets to try to stop a "virus" from wiping out their computer.
The typical scenario portrays a concerned tech from a reputable company calling to inform you that they have received an alert signaling your computer is infected. The tech claims to be from Microsoft or Apple and requests permission to remotely login to your computer to remove the virus. It's a very convincing pitch. Once they have access to your computer they open up legitimate system logs & files, but use them as evidence that your system has been breached. Most people can't identify these logs, so they take the scammers word for it, and proceed to pay the scammer to clean the "infected" system for a relatively low price. The fee varies, but is usually in the range of $100-$200. Once the scammer knows they can get a little money from you, a bigger step is taken to try to get even more.
If the initial scam wasn't terrible enough, during this time logged into your system the scammer could also be installing much more harmful software designed to steal things like credentials for accessing your banking info.
The scammers script generally continues at this point by saying you need additional protection at a much larger price. You have already been breached once, why let it happen again they argue? The scammer makes a calculated decision based on how well the initial fleecing went to price their next "service." It's often in the $1,000 range for them to install "special" software to protect you in the future. It isn't until this point that many people start to wonder if they're being taken for a ride.
If someone calls you from Microsoft or Apple and tells you your computer is infected, hang up. If you are worried, call a trusted IT Professional & explain the situation. You wouldn't let a stranger into your house. Similarly, don't allow someone into your computer who you don't know and haven't requested service from.