It was just a few days ago that we reported about the Desktop gadgets being removed from the Windows 8 Operating System,which is all set to RTM in the first week of August.
Recently Microsoft released an automated fix which disables the Windows Sidebar and Gadgets in the Windows 7 and Windows Vista.The article indicates that the existing Desktop gadgets in the Windows 7/Vista operating system have some vulnerabilities which might threaten the security of the System.So due to these vulnerabilities some of the suspicious gadgets from the unknown sources can harm your computer.
This might also be the reason behind ditching the desktop gadgets in the final version of Windows 8 (earlier they were included in the Consumer Preview and the Recent Release Preview version of Windows 8).This might also open the doors for the developers to build alternative Metro apps which can replace the desktop gadgets as well as they can avoid any security attacks to the system.
Source[TechNet]