That helpful person calling from Microsoft Tech Support is most likely a scammer. The odds go up to 100% if they tell you they noticed a problem with your computer and are calling to help you fix it. You can easily test that premise by telling them they have just reached an FBI agent and asking for their real name.
Such surprise phone calls from Microsoft tech support are always scams. A legitimate call could result if a user initiated something with Microsoft in the preceding hours and is expecting a return call. The legitimate tech support phone call will be following up on the specific issue that was raised. The scam callers will try to learn a victim’s password or credit card information or to trick them into surrendering access to their computer.
Real tech support: “OK, please reboot your computer and see if that helped.”
Fake tech support: “OK, I’m going to send you something that will solve the problem, just log into it with your username and password.”
For more information see Avoid tech support scams from Microsoft. Share this information with your relatives and clients. It is good content for a law firm newsletter.