Hi Rishi,

This this post below by dean-dean should help:

<quote>

Right-click Command Prompt and Run as Administrator. Type the following command:

winmgmt /verifyrepository

If the system returns "WMI repository is not consistent", run this command:

winmgmt /salvagerepository

The first time you run this it will fail. It will issue stop commands to
the services causing it to fail. It might take a couple minutes for the
services to shut down. Run the command again. You actually may have to run
it 3 times before it finally runs and completes on its own.

Reboot your system.

</quote>

--
Regards,

Ramesh Srinivasan, Microsoft MVP [Windows Shell/User]
Windows® Troubleshooting [url]http://www.winhelponline.com[/url]
Winhelponline.com blog [url]http://www.winhelponline.com/blog[/url]


"Rishi" <rishianitstigma******.com> wrote in message news:220373c2-34e2-4b1e-993e-1c3132161d6c@n58g2000hsf.googlegroups.com...
My security center reports my Windows defender as turned off.However
when i am trying to enable it by clicking "Turn on now" button,it
prompts UAC and than nothing is changed. I have PC tools antivirus
installed as a virus scanner.Does it affects the Windows defender?