Turn on the protection you already have
Windows 10 and 11 include Microsoft Defender for free. Open Settings → Privacy & security → Windows Security and check that "Virus & threat protection" is on. One good antivirus is enough: two at the same time slow the computer down.
Update everything
Most attacks use old holes that updates already fixed. Run Windows Update, update your browser (Chrome, Edge, Firefox) and remove programs you never use.
The 6 habits that block most infections
- Never open attachments you did not expect, even from a friend (their account may be hacked).
- Download programs only from the official website or the Microsoft Store. "Cracked" software is the number-one source of viruses.
- Scan every USB key before opening files: right-click → "Scan with Microsoft Defender".
- Use a different password for email and for mobile money, and turn on two-step verification.
- Do not click "Allow notifications" on unknown websites.
- Back up important files on an external disk or Google Drive / OneDrive every week.
My computer is already infected: step by step
- Disconnect from the internet (WiFi off, cable out).
- Run a full scan with Microsoft Defender, then the Microsoft Defender Offline scan (Windows Security → Scan options).
- Uninstall programs and browser extensions you do not recognise.
- Reset your browser settings.
- From another, clean device, change your email, Facebook and banking passwords.
- If the computer is still slow or shows strange windows, back up your documents and reinstall Windows.
Free tools that help
- Microsoft Defender (built into Windows)
- Malwarebytes Free: second-opinion scan, from malwarebytes.com only
- Bitdefender Antivirus Free: for older PCs
Download only from the official websites. A "free antivirus" offered in a popup is almost always a scam.
Links checked on 09/10/2026. General information only: rules and fees can change, so always confirm with the official office.