It is a scam to gain access to your PC by eventually getting you to allow them remote access and or ask for more personal info like your full name, address, credit card info and any other personal info which they could use to steal your identity.
No one, I repeat NO ONE "monitors" your PC for "errors" INCLUDING MICROSOFT. So if anyone calls stating they are Tech support for MS or any other company, HANG UP.
Never, ever reveal ANY personal information to ANYONE who cold calls you.
Never, ever give out bank account numbers, credit card numbers, SS numbers to ANYONE who CALLS you.
Never, ever agree to ANYTHING over the phone unless YOU personally called that service.
Never, ever open email attachments unless you know ahead you will be getting an attachment.
Never, ever respond to emails from "banks" which state your account is being suspended unless you "verify" by using a link in the email. Banks will never reach out to you in this manor (this includes credit cards).