Updates for Windows Defender are usually included in
regularly scheduled Windows updates. However, you can manually download and
install the updates yourself.
Updates may be available in several places online, but only
download those from Microsoft's official website.
Files from other sources may in fact be viruses or other malware
disguised as legitimate update files.
Log into your Windows Vista computer as an administrator.
You will need administrator rights to install the update
Check whether you are running the 32- or 64-bit version of
Windows Vista by clicking on the "Start" menu, then typing
"system" in the search box and clicking "system" in the
For the "System type" entry you will see either
"32-bit operating system" or "64-bit operating system".
Download the update definition files from Microsoft's
There are different versions of the files for the 32- and
64-bit versions of Windows Vista, so be sure to download the correct version
for your computer by simply clicking the appropriate link (see Links below),
which will start the download automatically.
Click "Run" when the download has completed to
immediately begin installation.
Follow the prompts on your screen to complete the
installation, and restart your computer if necessary.
A restart is not usually required immediately, but is
usually required in order for installation to be fully completed, so restart as
soon as possible.