Assumption: You already have Microsoft Security Essentials installed in your PC and want to update the virus signature database manually because of no internet connection or bandwidth usage limit or you just want to!
Requirement: You must be logged on to Windows as an Administrator.
1. If you are running 32-bit (x86) version of Windows:
If you are running 64-bit version of Windows:
2. If you want to install the virus definition update immediately without saving the file click Run or else save the file by clicking Save, please do remember the location of the saved file.
3. Time for installation!
on Windows XP:
Double-click the saved file, then click OK.
on Windows Vista/ Windows 7:
Right-click the saved file and choose Run As Administrator. If prompted for password/confirmation, please enter the password or click Continue.
4. A file extraction dialog box appears and installs the update.
Then after the dialog box closes you can verify the updated definition version from Microsoft Security Essentials > Update > virus definition version | spyware definition version.
5. Your computer is a bit more secured now! Enjoy!
I think computer viruses should count as life. I think it says something about human nature that the only form of life we have created so far is purely destructive. We've created life in our own image. — Stephen Hawking