Disable screen blank in X
Disable your X server from blanking the screen
When watching DVD's or whatever on your machine, you may find that Xorg blanks the screen after 10 minutes of inactivity.
To disable this simply add the following to your xorg.conf
Section "ServerFlags" Option "blank time" "0" Option "standby time" "0" Option "suspend time" "0" Option "off time" "0" EndSection