hi nevet, I am having the same problems and was wondering if you figure out
the solution. i have try all the suggestion with no luck.

"dean-dean" wrote:

> Hi Nevet. You might try this. Go to the main Windows Update window and
> click on "Installed Updates" (on the left-hand side of the window, at the
> bottom), and then remove "Update for Microsoft Windows (KB931099)" (only).
> Reboot. Reboot again. Go back to Windows Update, and re-install the same
> update, by clicking on the Check for Updates button.
>
> This should essentially re-install Windows Defender on Vista.
>
>
> "Nevet" <Nevet@discussions.microsoft.com> wrote in message
> news:41903B05-21DC-479F-8C51-2250FE3BDF06@microsoft.com...
> > Thanks, Engel! This looked right, but doesn’t seem to apply to Vista.
> > Running appwiz.cpl, Windows Defender doesn't even show up on the list of
> > installed Program and Features, nor under Windows features to turn on or
> > off.
> > It is also not listed in the Windows Installer CleanUp utility
> > (http://support.microsoft.com/kb/290301/). And when I try to reinstall
> > from
> > http://www.microsoft.com/athome/secu...yware/software, as the KB
> > article
> > instructs, I get the message “You do not need to install this software
> > because Windows Defender is included in Windows Vista. You can access
> > Windows Defender from the Security section of the Windows Control Panel.”
> >
> > Windows Security Center shows (under “Malware protection”) that Windows
> > Defender is turned off. “Turn on now” churns for a while, then says,
> > “Security Center can’t turn on Windows Defender. Please try again
> > later.”
> >
> > Any other ideas?
> >
> >
> > "Engel" wrote:
> >
> >> Hello Nevet,
> >>
> >> Error message when you run Windows Defender: "Error Code 0x800106ba
> >>
> >> Try this
> >> http://support.microsoft.com/?kbid=931849
> >>
> >>
> >> I hope this post is helpful.
> >>
> >> Let us know how it works ºut.
> >>
> >> --
> >>
> >>
> >>
> >> "Nevet" wrote:
> >>
> >> > Running Vista Home Premium. When starting the OS, I get an error
> >> > message
> >> > from Windows Defender:
> >> >
> >> > "Application failed to initialize: 0x800106ba. A problem caused Windows
> >> > Defender service to stop. To start the service, restart your computer
> >> > or
> >> > search
> >> > Help and Support on how to start the service manually."
> >> >
> >> > Attempting to manually start the service brought up another error:
> >> >
> >> > "Windows could not start the Windows Defender service on Local
> >> > Computer.
> >> > Error 0x80092003: An error occurred while reading or writing to a
> >> > file."
> >> >
> >> > I have uninstalled my third-party (McAfee) security suite so Defender
> >> > is all
> >> > I have on this machine.
> >> >
> >> > I found similar reports on various newsgroups but no solution,
> >> > workaround or
> >> > fix offered.
> >> >
> >> > Any suggestions?
> >> >
> >> > --Nevet
>
>