Defender Antivirus 8

Microsoft is adding a bunch of significant new security features in
Windows 8, including Early Launch Anti Malware (ELAM), Unified
Extensible Firmware Interface (UEFI), and the first edition of Windows
Defender to protect not just against malware but also against viruses.
In this article, we'll describe Windows 8's overall security feature
set, while also reviewing the new Defender and drawing comparisons
between Defender and other antivirus (AV) packages, including the
pre-existing Microsoft Security Essentials (MSE).

 Download the latest Windows Defender updates for your PC

You can install the definition file immediately, or save it to your PC first.

• Tap or click Run to install the definition file immediately.


• Tap or click Save to save the file to your PC. Make sure you remember the name of the folder where you save the file.

To install the definition updates from a saved file:

1. Use the Search charm on the Start screen to locate the folder where you saved the definition file.


2. Run the file:
   
   
   
   • If you're running a 32-bit or 64-bit version of Windows, press and hold (or right-click) mpam-fe.exe, tap or click Run as administrator, and then tap or click Run. You might be asked for an admin password or to confirm your choice.
   
   
   • If you're running Windows RT, press and hold (or right-click) mpam-fe.exe, tap or click Run as administrator, and then tap or click Run. You might be asked for an admin password or to confirm your choice.
   
   
   
   

Note: If you don't have an administrator account on the computer,
ask an admin to sign in and install the definition file for you

Windows 8

Download 32

Download 64

 Windows 7,Vista and Xp

 Download 32

Download 64