Have started seeing this a lot. You have uninstalled an AV but Windows still reports it as being there in the Security Center.

To get rid of this message, click Start, Run. Type ’services.msc’ and enter.

Now find Windows Management Instrumentation Service and stop it.

Now open Wndows Explorer and Delete the Repository folder under c:\windows\system32\wbem\

Now restart the WMI service and Windows should start reporting the AV situation correctly.

If you can’t delete the folder then you may have to disable the WMI service and reboot. Then delete the folder, change the WMI service back to Automatics and reboot again.