Yes it is a SCAM!
Avoid tech support phone scams
In USA you can contact FBI, State Attorney General, local law enforcement and
consumer watch groups. Arm yourself with knowledge.
The Internet Crime Complaint Center (IC3) is a partnership between the
Federal Bureau of Investigation (FBI) and the National White Collar Crime Center
(NW3C), funded in part by the Bureau of Justice Assistance (BJA).
No, Microsoft would not call you unsolicited. Nor would they know if any errors
existed on your computer. So those are frauds or scams, to get your money or
worse to steal your identity.
Avoid scams that use the Microsoft name fraudulently – Microsoft does not make
unsolicited phone calls to help you fix your computer
Microsoft Consumer Support Center
Microsoft – Contact Support
Hope this helps.