A warning filled the screen and told you to call a number.
It may be red, it may be full screen, and it may talk. It says the computer is infected or locked, and it gives a number. Security warnings come from the software that protects the computer, so telling you to act feels like part of the job.
Real security warnings do not include a phone number. The FTC says so directly, and so does Microsoft: its error and warning messages never include one. A number on the screen means the screen is an advertisement.
What it is
In these cases the warning is usually a page in your browser. Microsoft describes pages that put the browser into full screen, show messages that won’t go away, and sometimes add a fake blue screen, a fake Windows activation box, or audio. The aim is a phone call. The FTC describes what comes next: the caller asks for remote access, fakes a scan, finds a “problem,” and asks for payment that is hard to recover.
The next few minutes
- Don’t call the number and don’t click inside the box. The FBI’s Internet Crime Complaint Center gives the same instruction for pop-ups, texts, and emails.
- Close the browser. If the page won’t let you, restart the computer. You lose whatever was unsaved in the browser, which is a small cost next to a stranger on the line with access to the computer.
- Don’t search for “support” to find a real number. The FTC warns that numbers in search results aren’t always legitimate. If you want to reach your security software’s company, use the number on its website, your receipt, or the packaging.
- Photograph the screen before you close it, if you can, with the number and any ID on it. Write down the time.
If someone already called
What to do depends on what the caller got. Go down this list and do each one that applies.
- They connected to the computer. Uninstall any program they had you install. Microsoft suggests resetting the device if they had access, running a full Windows Security scan, installing available updates, and changing your passwords. The FTC adds two-factor authentication. Change passwords from a different computer.
- You gave a password. Change it, and change it anywhere you reused it. If you’re locked out, the FTC’s account-recovery pages apply.
- You paid by card. Call the card issuer at the number on the card and ask for the charge to be reversed.
- You paid with gift cards, a wire, or cryptocurrency. Contact the card issuer, the wire company, or the exchange right away. The FTC says cryptocurrency lacks the legal protections cards have, so recovery is harder.
- You signed in to your bank while they were connected. The FBI describes callers capturing the login and making transfers while the screen goes black. Call your bank’s fraud department the same day.
Write it down for the person who runs IT
- Which computer and whose sign-in, and the time you first saw the warning.
- The phone number on the screen, the number that called back, and anything said, including any name or website they gave.
- Any program they had you open or install, and any amount or account that moved.
- Who else saw the number. Colleagues may get a call from the same people.
Where to report it
Report to the FTC at ReportFraud.ftc.gov, to the FBI’s Internet Crime Complaint Center at ic3.gov, and to Microsoft at microsoft.com/reportascam. Include the phone numbers and any accounts that received money. The FBI also asks you to keep all original documentation and records of the conversations.
What closing the box tells you
Closing the browser ends the pop-up. It doesn’t show whether anyone connected to the computer before that, whether a program was installed, or whether the browser’s settings were changed. If you never called and never clicked, the risk is low. If you did either, treat the computer as one that needs a look before it is trusted again.
We look at the computer with you, including remote-access programs and browser settings, and tell you what we found and what we didn’t, with dates.
The number on that screen leads to a person whose job is getting access to your computer and your money.
Related
Sources
- FTC: How To Spot, Avoid, and Report Tech Support Scams
- FTC: What To Do if You Were Scammed
- Microsoft Support: Protect yourself from tech support scams
- Microsoft Support: Avoid and report Microsoft technical support scams
- FBI IC3: Public Service Announcement on tech support and refund scams (July 2023)
- FBI IC3: Public Service Announcement on remote access and bank accounts (November 2022)
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Written by Craig Peterson, 35+ years successfully running IT and security for businesses. Last reviewed October 27, 2026.