Have a security alert

The behavior described matches a fake “tech support” or “Windows Defender/Microsoft security” scam pop‑up in the browser, not a real Microsoft alert that locks Windows or warns that shutting down will spread a virus.

Actions to take immediately

1. Do not call any phone number shown and do not follow any instructions on that page.
2. Close the browser that shows the alert:
   • Press Ctrl+Alt+Del and open Task Manager.
   • In Task Manager, select the web browser process (for example, Microsoft Edge, Chrome, Firefox) and choose End task until the browser closes.
   • If that fails, hold the power button until the PC turns off, then turn it back on.
3. When the browser restarts, if prompted to “Restore previous session/pages,” choose No so the fake alert page is not reopened.
4. Clear the browser cache and site data (history, cookies, cached files) so the malicious page does not reload from history.

Key points about these scams

• Microsoft does not send unsolicited pop‑ups with phone numbers or messages that say the computer is locked and must not be shut down.
• Error and warning messages from Microsoft never include a phone number to call.
• These scam pages often run full‑screen, play sounds, and block normal controls to make it appear that Windows is locked, but they are just browser pages.

How to protect against this in the future

• Be cautious of pop‑ups claiming to be from Microsoft, Windows Defender, or Windows Security that:
  • Show a phone number to call.
  • Claim all devices are infected or data is on the “dark web.”
  • Demand remote access or payment.
• Use Microsoft Edge with Microsoft Defender SmartScreen to help block known scam sites.
• Install a reputable ad blocker extension in the browser to reduce malicious or misleading ads that can cause these pop‑ups.
• If a similar pop‑up appears again, close the browser via Task Manager instead of interacting with the page.

If no software was installed, no remote access was granted, and no personal or financial information was provided, the system is typically not compromised; the issue is limited to the browser session.

References:

• Protect yourself from tech support scams
• possible virus, computer locked - Microsoft Q&A
• Microsoft Defender Scam or Do I have a virus on my computer - Microsoft Q&A
• Disabled computer - Microsoft Q&A
• How do I report a possible scam from Microsoft? - Microsoft Q&A
• why can't you block AnyTech365.com....they are a scam company posing as Microsoft supported, stealing information? - Microsoft Q&A