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Scam library · Tech support · Seniors

Microsoft virus warning pop-up scam

Your browser suddenly goes full screen, an alarm or voice plays, and a blue 'Windows Defender' or 'Microsoft Security' warning says your computer is infected and locked. Do not restart. Call Microsoft support now.

Nothing is wrong with your computer. It's a web page designed to look like Windows and to scare you into calling.

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What the message looks like

Pop-up on the screen · example, not real

From: Full-screen browser page (support-windows-alert[.]live)

Subject: Windows Defender Security Center

** ACCESS TO THIS PC HAS BEEN BLOCKED FOR SECURITY REASONS **

Your computer has alerted us that it is infected with a Trojan spyware. Your passwords and banking data are at risk.

Call Microsoft Support: 1-844-555-0163 (toll free). Do not restart your computer.

This is a made-up example. A real Windows warning would never show a phone number or appear inside your web browser.

How this scam works

These pages are reached through bad ads, mistyped web addresses or hacked sites. They use tricks to look stuck: full screen mode, repeated dialog boxes, and a fake cursor. They can't actually take over your computer.

Microsoft says its real error and warning messages never include a phone number, and it doesn't make unsolicited calls offering support. The number on screen goes to scammers who ask for remote access, then charge hundreds for fake repairs or move into a fake refund or 'your bank was hacked' story.

The FBI counted $2.13 billion in reported tech support losses in its 2025 Internet Crime Report. Many victims are older adults, which is why it's worth showing your parents what this pop-up looks like before they see it.

Red flags

  • A phone number on a security warning. Microsoft's real warnings don't have one.
  • It appeared while you were browsing, inside the browser.
  • Alarms, a robotic voice, or a countdown.
  • 'Do not restart or shut down your computer.'
  • Claims that your bank details or passwords are being stolen right now.

How to tell it’s fake

  1. Press Esc to leave full screen, then close the tab or the browser. If it won't close, press Ctrl+Shift+Esc (Windows) to open Task Manager and end the browser, or restart the computer.
  2. When you reopen the browser, don't restore the previous tabs.
  3. If you want to check, open Windows Security from the Start menu. That's where real Windows alerts live.

What to do if you clicked, paid or shared info

Don’t panic, and don’t blame yourself. These scams are built by professionals. Act quickly, one step at a time.

If you clicked a link or called back

  • If you called but didn't give access, hang up. Don't answer if they call back.
  • If they connected to your computer, disconnect from the internet, uninstall the remote tool (names like AnyDesk, TeamViewer or ScreenConnect) and get the computer checked by someone you trust.

If you paid

  • Call your bank or card issuer right away using the number on your card. Ask them to stop any payment, wire or transfer.

If you shared personal info, a password or a code

  • If you logged in to anything while they were connected, change those passwords from a different device and turn on two-step verification.

Where to report and get help (U.S.)

If a message seems legit and you’re still not sure, get a second opinion before you act. Reporting helps stop scammers, even if money can’t be recovered. If you are in danger, call 911.

  • Your bank or card issuer
    Call the number on the back of your card or on your statement, not one from the message. Ask them to stop or reverse the payment and to watch the account.
  • Federal Trade Commission (FTC) · ReportFraud.ftc.gov
    Report the scam and get a step-by-step recovery plan.
  • FBI Internet Crime Complaint Center (IC3) · ic3.gov
    Report scams that happened online, especially if money was lost. Include phone numbers, websites and payment details.
  • AARP Fraud Watch Network Helpline · aarp.org helpline
    Free, for anyone of any age: trained volunteers help you sort out next steps. 877-908-3360, Monday to Friday, 8 a.m. to 8 p.m. Eastern.
  • IdentityTheft.gov · IdentityTheft.gov
    If you shared your Social Security number or someone opened accounts in your name.

How Gmork Scam Guard would warn you

Scam Guard runs in Chrome and Edge on your computer. It recognizes a fake Microsoft warning page by its behavior and wording and steps in with a calm message: this page is not from Microsoft, there's no virus, here's how to close it. It's an expert voice right when the alarms are going off, which is when people make the call. If something still seems legit, get a second opinion before you dial.

Scam Guard can miss things, so the checks above still matter. See what it warns about and what it keeps private.

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Questions people ask

Is the Microsoft pop-up with a phone number real?
No. Microsoft's real warnings never ask you to call a phone number. Close the browser.
Is my computer infected after seeing it?
Usually not. The page is just a web page. Close it and don't restore tabs. If you installed anything it suggested, uninstall it and run a scan.
I let them connect. Can they still get in?
Possibly, if the remote tool is still installed. Remove it, have the computer checked, and change passwords from another device.

Sources

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