Microsoft released the public beta of the stand alone system sweeper tool.
Microsoft Standalone System Sweeper Beta, a recovery tool that can help you start an infected PC and perform an offline can to help identify and remove rootkits and other advanced malware. In addition, Microsoft Standalone System Sweeper Beta can be used if you cannot install or start an antivirus solution on your PC, or if the installed solution can’t detect or remove malware on your PC.
Microsoft Standalone System Sweeper Beta is not a replacement for a full antivirus solution providing ongoing protection; it is meant to be used in situations where you cannot start your PC due to a virus or other malware infection.
You can download the tool here.