Windows Defender Offline Tool

Windows Defender & Windows Defender Offline Tool:

Windows Defender as earlier, it is a part of your Windows system.  Windows Defender is your first line of defense against spyware and other unwanted software. And in Windows 7, it's easier to use, with simpler notifications, more scanning options, and less impact on your computer's performance.

A new feature called "Clean System" provides one-click purging of all suspicious software, and Windows Defender is now part of Action Center, the streamlined place for keeping your PC running smoothly.

The primary benefit of using this tool is that it runs before malware, such as rootkits, can hide. When you perform a post-event malware scan and remediation by running the scan on a system infected with advanced low-level malware, the malware has a chance to run first. The malware itself may be intercepting the antimalware software’s attempts to inspect, take actions, or communicate to the user. When you run an “offline” tool like Windows Defender Offline, you’re bringing your own known-good, clean operating environment with you along with the scanner. You are booting the computer from that clean operating environment, and then running the scanner and inspecting the potentially compromised hard disk’s operating system, programs and data. As such, there’s integrity in the system during the “offline” scan. Malware that’s deeply rooted in the operating system won’t have the opportunity to run and hide before the scanner starts. The malware exists on the disk where it can be found and mitigated but is not actually running, so it’s inhibited from being able to intercept and interfere with the scanner’s activities.

Microsoft provides both a 32-bit and 64 -it version of the software for download:

Because Windows Defender Offline works from a clean environment, it's a good idea if you can get access to another computer running Windows that you know is free from infection. You can use this "known-good" computer to download and install Windows Defender Offline onto removable media, such as a CD, DVD or USB flash drive, as described in Step #1 below. Using a second, known-good computer will ensure that any malware you may have on your infected PC doesn't interfere with the download of Windows Defender Offline.  If you can't use a separate, known-good computer, then by all means it's worth trying to download and install the tool with the infected PC, however Windows Defender Offline may not operate correctly.