I have a notice that I must contact Microsoft and do not turn off computer ...is this a scam

Sounds like a scam to me.

This FTC alert is about criminals who pretend to be from Apple and Amazon – but substitute "Microsoft" and the scam is much the same.

https://consumer.ftc.gov/consumer-alerts/2020/12/fake-calls-apple-and-amazon-support-what-you-need-know

Here's what Microsoft has to say:

https://support.microsoft.com/en-us/windows/protect-yourself-from-phishing-0c7ea947-ba98-3bd9-7184-430e1f860a44

And Apple:

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

This is most likely a scam. Dismiss the notification. If you’re Getting the notification on a pc or mac, you can scan the device with the Free version of malwarebytes