This from The Windows Club:
Firstly, this isn’t antiviral software and isn’t meant to take the place of your antivirus.
Microsoft Standalone System Sweeper Beta is a recovery tool that can help you start an infected PC and perform an offline scan to help identify and remove rootkits and other advanced malware. It can also be used if you are unable to start or install an antivirus solution on your PC because it creates a bootable disk.
Also, if your installed antivirus cannot detect or remove malware on your Windows PC, this tool could be of help.
From the MS Download page:
“To get started, please make sure that you have a blank CD, DVD, or USB drive with at least 250 MB of space. Next, download and run the tool – the tool will help you to create the bootable media required to run the software on your PC.”
There’s an x32 and x64 version.
What? You're still here?
Download page: Microsoft.
Source: http://www.thewindowsclub.com/microsoft-introduces-system-sweeper-tool-a-recovery-tool-for-an-infected-windows-pc#ixzz1NrdAa23z