Microsoft Malware Protection Center (MMPC) is now Windows Defender Security Intelligence (WDSI). Watch out for even more info about threats and protecting you and your Windows computer.
Alert level: Severe Detected with Windows Defender Antivirus
Also detected as: Win32/MBRlock.D (ESET) TR/Ransom.Mbro.ahlx (Avira)
Windows Defender Antivirus detects and removes this threat.
This threat stops you from loading Windows and displays a full-screen message, commonly called a "lock screen". If this threat asks you to pay a fee or fine, do not pay it. The message is a fraud.
It tries to scare you into paying a fine to unlock your PC.
Our ransomware FAQ page has more information on this type of threat.
Windows 10 protects you from ransomware. Read Windows 10 Creators Update provides next-gen ransomware protection for details.