Open Windows Security
Search for Windows Security in the Start menu and open Virus & threat protection.
Make sure protection is on
Under Virus & threat protection settings, Real-time protection should be On. If another antivirus is installed, Windows will say it is being used instead.
Run a Quick scan
Click Quick scan. It checks the places where threats usually hide and takes a few minutes.
Run an offline scan if you're still worried
In Scan options, Microsoft Defender Offline scan restarts your PC and scans before Windows loads — useful for stubborn malware.
Watch for adware signs
Constant pop-ups, a browser home page you didn't choose, or new toolbars usually mean adware. Remove unknown programs in Settings → Apps → Installed apps.
Never call a number in a pop-up
“Your PC is infected — call Microsoft” messages are scams. Close the browser. Microsoft does not show phone numbers in warnings.
Do it in one click — freeAiActions PC Helper checks all of this for you in about a minute and explains what it finds in plain English. Free health check any time, plus one free fix session. Nothing changes without your OK.
Questions
Is Windows Security good enough?
For most home users, Windows Security (Microsoft Defender) gives solid built-in protection when it's switched on and up to date.
Someone remotely accessed my PC — what now?
Disconnect from the internet, don't log in to your bank on that PC, and change your passwords from another device. Then get it checked — call us on 0208 459 6264.