Windows 7 offers a variety of useful gadgets but user can install additional gadgets as well. By default, the user installed gadgets are enabled in Windows 7 but you can easily change the settings and can prevent all users from being able to install a gadget too. You will need to make a little change in the group policies, go through the following simple steps to achieve this.
Launch the Local Group Policy Editor by clicking Start, typing gpedit.msc and pressing Enter, once it is launched, browse to User Configuration > Administrative Templates > Windows Components > Desktop Gadgets.
Locate the Turn Off user-installed desktop gadgets option in the right pan and double click it. Another dialogue box will be displayed, choose Enable option from here.
Windows 7 will now run without user installed gadgets, this setting will be applied after you log off and log back in or simply restart your computer. Enjoy!