First, check to see if Defender is turned on:
Turn Windows Defender on or off
Turn Windows Defender real-time protection on or off
If it's on, let's see if manually updating Defender fixes the issue.
In the right frame, under ' Latest Definition Updates ',
click the appropriate link for either 32bit or 64bit, depending upon
which flavor of Vista the system is running.
*Save* the file
When the download is finished close the browser and any other open programs
Turn Defender off for now using the steps on the above Vista Help page
Locate the download and *right* click it and choose 'Run as
administrator'. Follow the UAC prompts.
After the definitions install, or even if they don't, restart the system
IF Defender did not AutoStart, go back and turn it on using the steps on
the Vista Help page.
If the definitions did not install please post the last 50 or so lines
of the WindowsUpdate.log located in the WINDOWS directory [folder].
MowGreen [MVP 2003-2008]
> Reposted with additional information because last post didn't yield a
> Vista Business Edition, avast! free edition, Windows Firewall.
> One Care is not being used, and !avast is the only run-time AV.
> Windows Defender is set to Auto-start.
> At start up, Security Centre gives me the message that Windows Defender is
> not turned on, despite it being set to auto-start. Using Security Centre to
> turn on WD results in a 5 mins+ search for updates, then it returns a
> message saying no updates are available, and WD is still turned off.
> However WD starts from the "All Programs" menu with no problems.
> Any ideas anyone?