Guide · malware and clean-up
Pop-ups, your computer is infected, and a PC crawling to a halt: cleaning it up properly
A scary your computer is infected, call this number pop-up and a genuinely slow PC are two different problems. One is almost always a scam, the other is usually fixable, and treating them the same makes both worse. Here is how to tell them apart and clean each up properly.
Last reviewed: 21 July 2026 · by Alien IT Solutions
First, separate the two problems
They feel like the same emergency. They are not, and the fixes are opposite.
! A full-screen infection warning
A warning that your computer is infected and you must call a number, often with a locked browser and a blaring voice, is almost always scareware: a scam, not a real infection.
! A genuinely slow machine
A PC that is genuinely slow, freezing or crashing is usually something ordinary: too many startup apps, a full or failing disk, or, sometimes, real malware.
The your-computer-is-infected pop-up
Real antivirus software doesn't beg you to phone a call centre. This pop-up is a tech-support scam. The number connects to a scammer who will ask for remote access to your computer and a payment to fix a problem you never had.
What to do:
Don't call the number, and don't install anything it tells you to.
Close the browser. If it won't close, force-quit it: Task Manager (Ctrl+Shift+Esc) on Windows, Force Quit (Cmd+Option+Esc) on Mac. On a phone, close the tab or the browser app.
Reopen your browser without restoring tabs so the same page doesn't reload. Clear the browser cache if it keeps reappearing.
That is usually the whole fix. The pop-up was a web page, not an infection. Scamwatch (scamwatch.gov.au) tracks these tech-support scams, and you can report one there. If someone talked you into it over the phone, the remote-access safety guide covers what genuine support does and does not do.
If you already called, or let them in
If you rang the number and gave someone remote access or a payment, treat it as a real incident:
Disconnect the computer from the internet.
Contact your bank immediately if you paid or shared card details. They can try to stop or reverse it.
Change your important passwords from a different, trusted device.
Uninstall any remote-access tool they had you install, such as AnyDesk or TeamViewer, if it was not already yours, and have the machine checked properly.
Report it to Scamwatch, and call IDCARE on 1800 595 160 if you shared identity details.
A genuinely slow PC: the clean-up order
If the machine is just slow, with no scam pop-up, work through it in order, cheapest and safest first.
Restart it
A machine that has not been rebooted in weeks clears up an astonishing amount with one restart.
Check startup apps
On Windows, open Task Manager, then the Startup tab. On Mac, open System Settings, then General, then Login Items. Disable things you don't need launching at boot.
Check disk space
A nearly-full drive slows a computer badly. Clear space and aim to keep a healthy margin free, roughly 10 to 15 per cent.
Scan with one reputable tool
On Windows, the built-in Microsoft Defender is fine. Run one full scan. Don't stack three cleaner apps, which often are the junk.
Update the OS and browser
Updates fix the bugs and security holes behind a lot of odd behaviour.
Check drive health
Constant freezing, clicking noises or files that won't open can mean a failing drive. See below.
When it is the hardware, not the software
If it freezes constantly, makes clicking or grinding noises, throws disk errors, or randomly won't boot, you may have a failing drive. That changes the priority completely.
Back up anything irreplaceable now, before you troubleshoot further. A failing drive can die mid-repair. The dead drive and deleted files guide covers the first hour when a drive is on the way out.
Stop running heavy scans and cleanups on it. They stress a dying disk.
A failing drive is a replace job, not a cleanup. And if the machine is simply old and has been getting slower for years rather than suddenly, that is a different question again: whether to upgrade or replace it.
When to stop DIY
Reimaging, wiping and reinstalling the operating system, is the clean reset when malware won't clear or the system is a mess. Back up your files first, and remember that if the drive itself is failing, that is a hardware job, not a software one. It is worth getting hands-on help when you gave a scammer remote access or money, when the drive is showing failure signs and the data matters, or when malware keeps coming back after a scan.
The short version
A your computer is infected, call this number pop-up is a scam: don't call, don't install, just close the browser. A genuinely slow PC gets fixed in order: restart, trim startup apps, free disk space, run one reputable scan, update, then check drive health. If you let a scammer in, disconnect and call your bank. If the drive is failing, back up first and treat it as hardware.
General guidance, not a diagnosis of your machine.
Pop-up scare, or a machine grinding to a halt?
Same Day IT can clean up, repair or replace a machine and recover data from a failing drive. We'll never ask you to install remote-access software off the back of a pop-up, and nor should anyone else. If you paid a scammer or shared card details, contact your bank first, then report to Scamwatch and call IDCARE on 1800 595 160. Tell us what happened through the contact form.