Ubuntu adds an icon to the desktop for every removable drive that you attach to your system. The icons can be hidden by these steps:
- Press Alt+F2 to bring up “Run Application” window.
- Type gconf-editor into the box, click “Run” to bring up Configuration Editor.
- Browse to apps > nautilus > desktop.
- Untick “volumes_visible” and close the window.
The drive icons would then disappear from the desktop. Remember that you can always access the drives from “Places”.