This policy setting allows you to restrict the installation of unsigned gadgets. Desktop gadgets can be deployed as compressed files either digitally signed or unsigned.If you enable this setting gadgets that have not been digitally signed will not be extracted.If you disable or do not configure this setting both signed and unsigned gadgets will be extracted.The default is for Windows to extract both signed and unsigned gadgets.
Policy path:
Windows Components\Desktop Gadgets 
Scope:
Machine 
Supported on:
Windows Server 2008 Windows 7 and Windows Vista 
Registry settings:
HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\Windows\Sidebar!TurnOffUnsignedGadgets 
Filename:
Sidebar.admx 
