All the major antivirus software firms offer their bootable rescue disks that can be used to boot into a heavily malware infested computer, clean the infection and put the Windows PC in a working state once again. Microsoft also offers a rescue disk for their free Windows Defender antivirus product. It can be used to detect and remove malware, potentially unwanted programs (PUPs) and rootkits from a Windows PC. You can use any blank CD or USB flash disk to create the Windows Defender Offline rescue disk. The blank CD or the USB disk must contain at least 250 MB of free disk space.
First of all you have to download the Windows Defender Offline rescue disk creation tool. The tool is available for 32-bit and 64-bit Windows separately. So if you want to disinfect a PC running a 64-bit Windows, you should download the 64-bit version of the tool. Similarly the 32-bit Windows requires 32-bit version of this tool. As you launch the tool, it will show you the basic requirements (a working internet connection for downloading the virus definitions and a blank CD or USB flash disk). You can click Next to continue.
After agreeing to the usual end user license agreement of Microsoft, you will have to choose what type of media you want to create – a bootable CD or a bootable USB disk. You can also choose to save the media as an ISO image that you can burn later to any blank CD. Before proceeding make sure that you have placed a blank CD in your optical disk writer or inserted a USB flash disk in your PC.
As you click on the Next button it will go ahead and start to download over 260 megabytes of files from the Microsoft servers. After the download is finished these files are processed and burned to your CD or copied to the flash disk. A message is displayed notifying you that the bootable Windows Defender Offline disk is ready.
You can now use this bootable Windows Defender Offline disk to boot into any Windows PC. 32-bit disk should be used for 32-bit Windows PCs and 64-bit disk should be used for the 64-bit Windows computers. As the PE environment loads, you will be asked if you want to run the Windows Defender and upon confirmation it will proceed with the scan and remove any threats detected.
Conclusion: Windows Defender Offline is a great rescue tool in your arsenal when dealing with malware infected computers that cannot be repaired using the usual tools or are not able to even boot properly due to the level of malware infection.
You can get the Windows Defender Offline from http://windows.microsoft.com/en-us/windows/what-is-windows-defender-offline.