You might have obeserved , when you install debian the hard drive partition icons are displayed on the desktopby default. It annoys some people (like me). To remove the icons from the desktop open gnome configuration editor
then goto /apps/nautilus/desktop
then uncheck the variable volumes_visible . Then the icons will disappear.
On the contrary if you want them to be on desktop , just follow the same procedure and check the variable volumes_visible