A full-screen warning that says your computer is infected is not a diagnosis. It is an advert for a phone number. Microsoft, Apple, Google, and UK broadband providers such as BT, EE, O2, Vodafone, Three, and Virgin Media do not cold-call you because a pop-up appeared. They do not put a support number inside a browser alert and wait for you to dial it.
Close the message without ringing the number. If you cannot close it, force the browser or the whole device to quit. Then run any checks yourself, or take the machine to a shop you chose. Do not give a stranger remote control because a page told you to hurry.
Pop-ups, phone numbers, and the full-screen trick
The usual pop-up uses alarm language. Your licence is invalid. Your bank details have been stolen. Windows or macOS is “locked”. A phone number is displayed in large type. Some pages play a sound. Some freeze the tab so that ordinary close buttons seem to fail.
A full-screen browser window can look like a system screen. It is still just a webpage. On a Windows PC, Alt+F4 often closes the window. On a Mac, you can force quit the browser from the Apple menu or by using the usual force-quit shortcut. On a phone or tablet, swipe the browser away from the app switcher. You can also switch the device off and on if that is simpler.
Do not click “call support”. Do not type commands the page suggests. Those commands sometimes download remote-access tools for you. If a family member is with you, ask them to help close the window rather than to ring the number.
Once the page is gone, search the number on WhoCalledMe if you noted it. Other people may have reported the same pop-up script. Reports describe what callers asked for. They do not prove that a particular private person committed a crime.
Cold calls that claim to be Microsoft, Apple, Google, or your broadband firm
Some scams skip the pop-up and ring you instead. The caller says they have detected viruses on your line, your router, or your PC. They may know your provider’s name. That is easy to guess in many areas. They may offer to “optimise” your Wi-Fi.
Genuine support for a broadband fault starts from a problem you reported, or from an engineer visit you booked. It does not begin with an unexpected call demanding remote access. Apple will not ring you out of the blue to remove a Mac virus. Google will not. Microsoft will not ask you to install AnyDesk or TeamViewer because a webpage flashed a warning.
If you think you have a real broadband issue, use the app or the number on your bill. Type the provider’s site yourself. EE, O2, Vodafone, Three, BT, and Virgin Media all have published contact paths. Use those after you have hung up.
Remote access is the point of the scam
The caller’s goal is to see your screen. They ask you to install AnyDesk, TeamViewer, or a similar tool, or to open a tool that is already there. They may dictate a code so they can connect. Once connected, they can watch passwords, banking apps, and email.
They often claim they will “refund a licence fee” into your bank. They tell you to open the banking app so they can watch the money arrive. What you may see is a large payment going out, or a request to approve a new payee. Some scripts show a fake refund on screen while a real transfer leaves.
If they have already connected, disconnect. Turn off Wi-Fi or unplug the router if you need a hard stop. Uninstall the remote-access software. Do not follow further instructions from the caller.
Change important passwords from a different device, one they never viewed. Start with email, because email resets everything else. Then change banking passwords and app passcodes through official apps. Contact the bank using a number on your card or by calling 159 if a UK bank account was opened on the shared screen.
After you have closed the pop-up
Run a scan with security software you already trust, if you use it. You do not have to buy a package the caller named. A local repair shop can check a machine if you are not confident. Paying a shop you walked into is different from paying a voice that appeared with a pop-up.
Take Five. Stop the call or the page. Challenge the claim through a channel you chose. Protect passwords and bank access from a second device.
If you typed card details, tell the card issuer. If you sent money, tell the bank it may be fraud, including authorised push payment fraud if you confirmed a transfer. Report it to Action Fraud. GOV.UK Stop Think Fraud explains the wider habit of pausing on unexpected technical threats.
Keep a short note: time, number, whether it started as a pop-up or a cold call, and whether they asked for AnyDesk, TeamViewer, or a bank app. Do not write passwords. Do not photograph one-time codes.
Report the numbers without naming a culprit
Tech-support scams rotate numbers. A pop-up may show one line. A callback may use another. A “senior engineer” may ring from a third. Search each number on WhoCalledMe. Put them all on one factual report. Say it was a virus warning. Say they wanted remote access. Do not paste your IP address, device serial numbers, or account emails.
Block the number on the phone if it keeps ringing. Blocking does not identify an offender. If a new number repeats the same Microsoft or broadband story, add it to the same report.
You do not owe a conversation to a page that locked itself on purpose. Alt+F4, force quit, and a call you place to a provider you already pay are enough. Remote access is a house key. Do not hand it to someone who knocked by covering your screen in red text.
Common warning signs
- A pop-up says your device is infected and lists a phone number.
- The caller wants AnyDesk, TeamViewer or similar software installed.
- They ask you to type commands or open your bank app “to check the refund”.
- They want payment for a support package you did not order.
- They refuse to let you hang up and call the company yourself.
What you should do
- Hang up and close any warning pop-ups.
- Do not install remote-access software for an unexpected caller.
- Use a trusted local repair shop if you are worried about a virus.
- If you gave access or payment details, contact your bank and change important passwords from a different device.
- Report the number on WhoCalledMe so other people can see the pattern.
