A full-screen warning appears on your computer. It’s red, it’s alarming, and it’s telling you to call a number immediately or your computer will be locked. Your heart sinks.
Before you do anything—take a breath. Nine times out of ten, what you’re looking at is a fake.
The difference between a real virus warning and a fake one
Real antivirus software (Windows Defender, Malwarebytes, etc.) gives you quiet notifications—usually a small pop-up in the corner of your screen, or a message inside the programme itself. They do not take over your entire screen. They do not tell you to call a phone number. And they are never urgent in a way that prevents you from closing them.
Fake virus warnings are the opposite. They’re dramatic. They fill the screen. They play alarm sounds. They display a phone number with a UK or US area code and insist you must call immediately to save your data.
That phone number connects to a scammer, usually overseas, who will pretend to be from Microsoft or BT or your broadband provider. They’ll ask to take remote control of your computer and then either charge you hundreds of pounds for fake “repairs” or install real malware while they have access.
How to get rid of a fake virus pop-up
In most cases, you can simply close it:
Press Alt + F4—this closes the active window on Windows. If the pop-up is a browser tab, this will close the tab.
Or try Ctrl + W—this closes the current browser tab without closing the whole window.
If neither works and the screen seems completely frozen:
- Press Ctrl + Alt + Delete—this brings up the security screen
- Select Task Manager
- Find your browser in the list (Edge, Chrome, Firefox)
- Right-click it and select End Task
Your computer is not infected simply because a scary message appeared. These pop-ups are delivered through web pages—just closing the page is usually enough.
After you’ve closed it
Once the pop-up is gone, it’s sensible to run a quick scan just to be sure nothing was installed before you noticed the warning.
Open Windows Security (search for it in the Start menu) and run a Quick scan. This checks the most common locations for malware and takes a few minutes.
If Windows Security isn’t installed or isn’t up to date, Malwarebytes offers a free scanner that’s widely trusted.
When should you be genuinely concerned?
There are situations where a pop-up might be pointing to a real problem:
- Your computer is running much slower than usual
- You’re seeing pop-ups constantly across multiple websites
- Your browser homepage has changed without you changing it
- You’re being redirected to websites you didn’t click on
These symptoms can indicate that something has actually been installed—either adware or, less commonly, malware. In this case, a proper scan and potentially a clean-up is worth doing.
What if I already called the number?
If you called the number shown in a fake pop-up and gave someone remote access to your computer, contact your bank immediately and tell them you may have been the target of a scam. Change the passwords for your email, online banking, and any other important accounts. Then get your computer checked by someone you trust.
This is unfortunately more common than people realise, and there is no shame in having been caught out—these scams are designed by professionals to be convincing.
If you’re not sure whether a warning is genuine, or if you think your computer may have been compromised, I visit homes across Falkirk and Central Scotland to help.
Find out more about laptop and computer help, or call 07944 156 453. No fix, no fee, 7 days a week.
Falkirk Tech Help—friendly in-home tech support across Falkirk and Central Scotland.