The scary pop-up

The scary pop-up

Risky ending

This is the scam. Giving a stranger remote access lets them do anything on your computer; the next step is usually a demand for payment.

The lesson: If this happens for real: disconnect from the internet, hang up, contact your bank if you paid, change passwords from a different device, get the computer checked, and report it at ReportFraud.ftc.gov.