Fake Virus Warning Pop-Up? Don't Call the Number
2 October 2026 · By Ethan Fernandes
Pop-up says "Your computer is infected, call Microsoft Support"? It's a scam. How to close it safely, and what to do if you've already called or let them in.
You're browsing normally when the screen fills with a warning. It might say "Your computer has been infected", "Windows Defender Security Warning", "Access to this PC has been blocked for security reasons" or "Call Microsoft Support" with a phone number. There might be a loud beeping sound or a recorded voice, the page may go full screen, and it may seem impossible to close.
This is a scam. Your computer is very likely not infected. The page is designed to frighten you into calling the number, where a fake "technician" will ask to connect to your computer and then ask for payment or bank details.
Quick answer
Don't call the number and don't click anything on the page. Close the browser: on Windows press Ctrl + Shift + Esc, select the browser and click End task; on a Mac press Command + Option + Esc and Force Quit the browser. When you reopen the browser, don't restore the previous tabs. Microsoft and Apple never put phone numbers in warnings like this.
Why This Happens
These pop-ups are web pages, not real warnings from your computer. You usually land on them through a misleading advert, a mistyped web address or a dodgy link. The page uses tricks to make itself hard to close, such as going full screen, repeating pop-up boxes and playing alarms. None of this means your computer is infected, and closing the browser removes it.
Microsoft, Apple, BT and your bank will never display a phone number in a pop-up asking you to call about a virus, and will never cold-call you about one. Anyone who does is a scammer.
How to Close the Pop-Up Safely
Windows:
- Press Ctrl + Shift + Esc to open Task Manager. If it doesn't appear, press Ctrl + Alt + Delete and choose Task Manager.
- Find your browser (Microsoft Edge, Google Chrome or Firefox) in the list.
- Click it and click End task.
Mac:
- Press Command + Option + Esc to open Force Quit.
- Choose your browser (Safari, Chrome or Firefox) and click Force Quit.
If the computer is completely stuck: hold the power button for 10 seconds to switch it off, then turn it back on.
When you reopen the browser, if it offers to restore pages or reopen tabs, decline. If the scam page reappears, close it again the same way and, in the browser's settings, set it to open a new tab page on start-up rather than continuing where you left off.
After Closing It
- Run a security scan for peace of mind. On Windows, open Windows Security > Virus & threat protection and run a Quick scan.
- Check your browser's notification permissions. Some scam sites trick you into allowing notifications, which then show fake alerts. In Chrome or Edge, look in Settings > Privacy and security > Site settings > Notifications (wording varies slightly) and remove anything you don't recognise. In Safari on a Mac, look in Safari > Settings > Websites > Notifications.
- Check for unfamiliar browser extensions and remove any you didn't install.
If You've Already Called the Number
Don't be embarrassed. These scams are professional and convincing, and they catch careful, intelligent people every day. What matters now is acting quickly.
If you only spoke to them and gave no details or access: hang up. You don't need to do anything else, but be alert for follow-up calls claiming to be from Microsoft, your bank or the police. They're part of the same scam.
If you let them connect to your computer:
- Disconnect the computer from the internet straight away. Turn off Wi-Fi or unplug the network cable. Then shut it down.
- From a different device (a phone or another computer), change the passwords for your email, online banking and any accounts you used on that computer, starting with email.
- Don't use that computer for banking or email until it's been checked. Scammers often install remote access tools such as AnyDesk, TeamViewer or similar software so they can return later.
- Turn on two-factor authentication on your email and other important accounts.
If you gave card or bank details, made a payment, or logged in to online banking while they were connected:
- Call your bank immediately using the number on the back of your card. You can also call 159, which connects you securely to most major UK banks.
- Explain what happened. They can block cards, watch for suspicious payments and advise on getting money back.
- Report it to Report Fraud (formerly Action Fraud), the UK's national fraud reporting service, online or on 0300 123 2040 (in Scotland, report to Police Scotland on 101).
Call your bank from a different phone if you can, or wait a few minutes after hanging up before calling out. Scammers sometimes keep the line open and pretend to be the bank.
How to Avoid It in Future
- Keep your browser and operating system up to date.
- Be cautious with adverts at the top of search results. Type the addresses of important sites yourself.
- Never allow notifications from websites you don't know.
- Agree a family rule: nobody lets anyone connect remotely to a computer unless they arranged the help themselves with someone they know.
For more on recognising these tricks, read our guide to spotting scam calls, texts and emails.
When to Get Help
If someone has had remote access to your computer, it's worth having it checked properly before you use it for anything important again. We can remove remote access tools and malware, check accounts and settings, and help you secure email and banking. Our tech help for seniors is designed for exactly these situations, and our computer repair service can clean and check the machine. Remote support is available once a computer is confirmed safe, and Senri Home engineers, who are DBS-checked and insured, visit across West and South West London seven days a week, 8am to 9pm. Book a visit or call or WhatsApp 07826 399715.
Related Reading
Common questions
No. Microsoft never shows phone numbers in virus warnings or asks you to call. These pop-ups are scam web pages designed to get you to phone fake support staff.
On Windows, press Ctrl, Shift and Esc to open Task Manager, select your browser and click End task. On a Mac, press Command, Option and Esc and Force Quit the browser, then don't restore old tabs when you reopen it.
Disconnect the computer from the internet and turn it off. From another device, change your email and banking passwords, call your bank on the number on your card or on 159, and report it to Report Fraud (formerly Action Fraud).
Simply seeing a scam pop-up doesn't usually infect your computer. The danger comes from calling the number, downloading what they suggest or letting them connect remotely.
Still stuck? We can fix it for you
Most problems like this can be fixed remotely today, anywhere in the UK, or with a home visit across West London. DBS checked, insured, 7 days a week until 9pm.
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