If you don't make use of Windows 7 gadgets or want to disable the use of them, then you can remove the functionality by following this tutorial.
First, type "Turn Windows features on or off" in to the start menu search box and press enter, or you can manually access this via Control Panel > Programs > Turn Windows features on or off. Once this is loaded, find the "Windows Gadget Platform" box and untick it, then click OK.
The gadgets menu and all desktop gadgets should now be gone! If you wish to re-enable this, just check the box and click OK instead.