Modern malware tries hard to stay invisible, but it almost always leaves traces. Catching them early can be the difference between a quick clean-up and a stolen bank login.
The seven signs
- Sudden slowdowns — cryptominers and spyware consume CPU in the background. Check Task Manager for unfamiliar processes at high usage.
- Pop-ups outside the browser — adware injects ads directly into Windows itself.
- A changed browser homepage or search engine — classic browser hijacking.
- Friends receiving messages you never sent — your email or social accounts may be compromised.
- Disabled security tools — many trojans switch off antivirus and Windows updates first.
- Unexplained data usage or network activity — data exfiltration happens quietly.
- New toolbars, extensions or programs you did not install.
What to do right now
Disconnect from the internet, run a full scan with a reputable antivirus, remove anything it flags, then change your most important passwords from a clean device and enable two-factor authentication. If the infection persists, a complete OS reinstall is the only certain cure.
Prevention beats cleanup: see our ranked comparison of the best antivirus software to get protected before the next attack.