This upgrade involves a reinstallation of Windows Defender. If this hasn't
worked, please proceed as follows.
1) download the new version and save it to a known location, such as the
desktop.
2) close all open Windows Defender, OneCare, or Internet Explorer windows.
3) double click on the downloaded file to install the new version over the
old one.
Once the installation has completed, leave the checkbox to do a definition
update and scan checked. When Windows Defender opens, it will sit for some
time--minutes, perhaps, while the definition update proceeds in the
background. Once the update completes, a scan should start. At that point,
you can close the application using the red X in the upper right corner.
The scan will continue, but no more input is needed from you.
Once the scan completes, you should be able to re-open Windows Defender and
not see any further update notice.
