Warning popup: 'your PC is infected – call Microsoft'

A full-screen warning with a siren cannot be closed. On the phone a 'technician' takes over the PC, presents harmless log files as 'viruses' and demands money — often by gift card or transfer. Warning signs: Microsoft/Apple never call and never show a phone number in your browser; Remote access is required; Payment by gift card; The window supposedly cannot be closed. What to do: Close the browser via task manager, uninstall the remote tool and change passwords from another device. Typical loss: 150–5.000 €.