https://www.us-cert.gov/ncas/tips/ST10-001
Learn to avoid FAKE antivirus software… Fake antivirus is malicious software (malware) designed to steal information from unsuspecting users by mimicking legitimate security software. It’s important to protect your computer from fake antivirus infection and to be able to recognize when an infection has occurred. Source: https://www.us-cert.gov/ncas/tips/ST10-001