No Screensaver in Gnome 3?

Problem: Screensaver although installed, doesn't seem to work. The issue appears to be that xscreensaver doesn't auto-start. (Check in 'System Monitor' to see whether this is the case.)

If it is, in home>.config>autostart create an empty text-file called  'xscreensaver.desktop' and paste in the following information and reboot (then check 'System Monitor' again):

[Desktop Entry]
Type=Application
Exec=/usr/bin/xscreensaver -nosplash
Hidden=false
X-GNOME-Autostart-enabled=true
Name=xscreensaver
Comment=Screensaver for xserver
Name[en_GB]=xscreensaver

* Fill in red fields as necessary for your system.

Making Icons Visible on the Desktop (Gnome 3)

Hit alt>F2 and type...

dconf-editor

Go to org>gnome>desktop>background and tick "Show Desktop Icons". If you want to remove the Computer/Recycle Bin/Mounted Volumes go to nautilus>desktop and untick the relevant boxes.