Backup your current -annoying but working- configuration, open a console and su to root, then:
cp /etc/X11/xorg.conf /etc/X11/xorg.conf_backup
Then open the file with your favorite editor, for example:
Add / replace this options in your /etc/X11/xorg.conf file in the ServerLayout section:
Option "BlankTime" "0"
Option "StandbyTime" "0"
Option "SuspendTime" "0"
Option "OffTime" "0"
Save and exit. Close all your windows and restart the X server with ctrl + alt + backspace.
Wait ten minutes and see
If after restarting de x server you find any problems and your desktop is not back, no worries. Login as root again with the su command and:
cp /etc/X11/xorg.conf_backup /etc/X11/xorg.conf
Let us know how it goes.