Deactivate Screensaver and Monitor Sleeping on Ubuntu 12.04 with Gnome Classic
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This hint was found here:
In order to deactivate the screensaver, execute this:
gconftool-2 -s /apps/gnome-screensaver/idle_activation_enabled --type=bool false gsettings set org.gnome.settings-daemon.plugins.power active false
In order to disable Monitor Sleeping, execute this:
gconftool-2 -s /apps/gnome-power-manager/ac_sleep_display --type=int 0