If these are coming up through Windows Update, you need
to update Silverlight (a browser plugin), but installing Windows Live Essentials is optional. You can right-click and "Hide update" if you don't want a particular update to show up again.
Live Essentials has some decent software in it, but if you don't want it, feel free to decline it.
Silverlight should stay up to date, however, so let that one install.
Edited by keyboardNinja, 11 April 2011 - 11:41 PM.