1. Click Start, All Programs, Windows Update.
If the update engine is taking you to Microsoft Update, you should change it
to Windows Update. To do this,
2. Click the "Change Settings" option in the left-hand pane.
3. Uncheck "Use Microsoft Update". (This can be re-applied later, after
Defender updates, by going to
http://www.update.microsoft.com/microsoftupdate/v6/vistadefault.aspx?ln=en-us )
Then try using Windows Update to download the Definition Update, by clicking
on Check for Updates.
Or try starting Windows Defender (Start Menu\Programs). If it starts, click
on the down-arrow to the right of the Help icon, and choose "Check for
updates". Let Defender check and download the update.
If Defender does not open, or if it opens, but doesn't download the update,
go to
http://www.microsoft.com/security/portal/
Under "Latest Definition Updates", choose your operating system type, 32-bit
or 64-bit, and try the manual download. Note here the instructions
pertinent to Vista:
http://www.microsoft.com/security/portal/ADL.aspx#top
