I got an automated call "From Microsoft" saying that they had stopped a virus on my computer and that I had to call to have it completely resolved. The only red flag is that the phone number was an off shore (To the US) number.
Not a big deal EXCEPT that the number was off shore. If you understand the way that the phone networks work, you can be charged a significant amount per minute for calling a "Fee for services" phone number. What is worse, because the number is off shore or international, you will be stuck for the charges. AND your local telco can not force a refund across the international boundaries.
In the real world, Microsoft ain't ever going to call you, unsolicited, to fix your computer. It just ain't going to happen. Microsoft has your money for the operating system and other software so have a nice life.
I got a similar scam call from a live individual purportedly from Microsoft about a virus on my computer. He wanted me to install "A permanent Fix." I told him that I don't have any computers at home but there are almost 2700 down at the server farm. "In traffic it will take me an hour to get there so give me your phone number and I'll call you back."
They usually just hang up. If they want to engage in conversation as to why no computer at home, I'll tell them, "I work all day in IT and the last thing that I want at home is another computer."
Why a return call phone number? I can give it to the authorities (FBI) and allow them to prosecute for wire fraud. With a real, non spoofed, phone number a physical address can be determined.