Hi. I'm David, and I'm happy to help you.
What you described appears to be a tech support scam. Your computer isn't actually locked or infected with a virus. It's just a malicious website stuck in full-screen mode to scare you into calling them.
Microsoft will never put a phone number on a security warning or tell you to call support to unlock Windows.
Here is how to close that screen safely:
- Press "Ctrl + Shift + Esc" on your keyboard to open the "Task Manager";
- Look for "Microsoft Edge" (or whatever browser you were using) in the list of processes;
- Right-click on it and select "End task". The scary screen should disappear immediately.
A few important things to keep in mind:
- When you open Edge again, it might ask if you want to "Restore tabs". Click "No" or close that prompt; otherwise the scam page will just pop up again.
- Clear your browser cache to remove any temporary files left behind: inside the browser, press "Ctrl + Shift + Del", set the time range to "All time", select "Cached images and files" only, and click Clear Data.
- Do not call that number under any circumstances.
- Your computer is perfectly fine. The scammers just want you to call so they can trick you into giving them money or remote access.
You can run a quick scan with the built-in Windows Defender just for peace of mind, but you are totally safe as long as you didn't call them.
You can find more information about this type of scam in the official Microsoft article at the link below.
https://support.microsoft.com/Office/protect-yourself-from-tech-support-scams
Feel free to ask any questions you may have.