computer locked up

Microsoft does not make unsolicited phone calls, display pop-up alerts in your browser to call a support number or send unsolicited email messages. This includes any messages using the Microsoft, Windows Defender or Windows Security name to call them at a toll-free support number to "fix or unlock your computer", warn about "virus infections", prompts to renew/activate subscriptions, prompts to confirm/verify orders for purchases, request personal/financial information, or ask that you pay for support. In some cases the scam may just indicate "Your computer is locked" or "blocked**"** with various warnings or reasons as to why.   

Any emails, phone calls and computer pop-up alerts from someone claiming to be an employee affiliated with Microsoft or Windows Support are scams.   Microsoft: Protect yourself from tech support scams clearly states ...

• Microsoft does not send unsolicited email messages or make unsolicited phone calls to confirm/verify orders for purchases, request personal/financial information, or to provide technical support to fix your computer
• If a pop-up or error message appears with a phone number, don’t call the number. Error and warning messages from Microsoft never include a phone number.

Microsoft and others have been warning folks about Email Phishing Scams and Tech Support Scams for years.  

• Not responding to or clicking on any link in an email or browser or calling any number listed on the page is the best way to deal with email and browser scams...then report them to the appropriate authorities.

• Not answering any questions and hanging up the telephone is the best way to deal with phone scammers...then report them to the appropriate authorities.  

Closing the web browser and then relaunching it usually eliminates the bogus warning message and is the best way to deal with these scams. If the browser freezes or hangs, you may have to close it with Windows Task Manager (Force Quit a Tab in Google Chrome) by selecting End Task. Afterwards, you should also clear your browser cache.   

If using Task Manager does not resolve the problem, perform a force-restart using the Power button (press and hold down the power button for at least 10 seconds until the screen goes off, release the button, then press it again) or perform a hard shutdown to forcibly turn off the computer completely by cutting the power for 10-20 seconds and then restart the computer. After restarting the computer and opening your web browser again click "No" if you see the prompt to "Restore Previously Open Pages".  

For more information about how these scams work and resources to protect yourself from scams, please read Beware of Phony Emails, Phone Calls, Tech Support Scams (Post #13).  

There are suggestions near the bottom (under What should you do...?) for dealing with scams that lock/block your computer and dealing with push notifications. There is also a list of security scanning tools to use in case the usual methods do not resolve the problem or you allowed remote access into your computer.  

Reporting Phone, Tech Support Scams, Fraud, Phishing & Extortion Scams (Post #13) <- scroll down

Microsoft will never reach out unless you initiate the conversation. In this situation, it sounds like a tech support scam. You should be able to either close the browser or restart your computer to make the message disappear. If that does not resolve the issue, you may need to get with an IT professional to diagnose the issue further.

You can reference a Microsoft Learn document on the subject below:

https://learn.microsoft.com/en-us/defender-endpoint/malware/support-scams?source=recommendations