The 866-248-1415 pop-up is malicious
Recently, many computer users complain that they receive a message which suddenly takes over their screen and states that "MICROSOFT SECURITY ALERT! SUSPICIOUS ACTIVITY OF INTRUSIONS DETECTED, WHISH IS TRYING TO REDIRECT YOU TO A VIRUS ATTACK SITE. THIS MAY HAPPEN DUE TO NOT HAVING OBSOLETE VIRUS PROTECTED SHEILD". The pop-up also includes a "Microsoft" support phone number which they have not called 1-866-248-1415.