Rule 1: don't download software from shady sites
The most common route to infection is installing a "free" version of paid software. Search "download Photoshop for free" and 9 out of 10 results contain malware. Paid software usually has free alternatives: GIMP instead of Photoshop, LibreOffice or Google Docs instead of Microsoft Office. Or simply buy a licence.
Rule 2: keep Windows updated
Most serious malware exploits vulnerabilities in outdated versions of Windows. Updates close those gaps. Turn on automatic updates and don't postpone them, especially security updates. Windows 10 has stopped receiving security updates since October 2025 — a strong reason to move to Windows 11.
Rule 3: don't click suspicious links
"You've won an iPhone!", "Verify your account immediately", "Urgent: your card has been blocked" — this is phishing. The goal: steal your passwords or install malware. Signs: urgency, fear, an offer that's too good, an unfamiliar sender. If in doubt, don't click.
Rule 4: you need antivirus, but not the one you think
Windows Defender, built into Windows 10 and 11, is more than enough for most users. Expensive third-party antivirus software isn't always better. What matters more: never disable Defender "for speed", and never install "antivirus" software from random internet sources — most of those are malware themselves.