if it is a UK sky HD box then the PSU may have failed a hard reboot is the best thing to try before phoning sky for an engineer visit.
Unplug/switch off mains power to sky box, hold down the "back up" button on the top of box (do not let go until instructed). Reconnect mains power, keep finger on "back up" after a few seconds you will see a row of LEDs illuminate on the front of the box, on TV you will see white text on black background that says "do not disconnect mains power satellite system updating" or similar. then release the back up button and leave the room for 30 minutes. when you come back box should be in standby, turn the ox on with remote (can take a few minutes for it to sort its self out) then you should be away and working.
IF you dont get any LED's come on its a new box I am afraid.
Toms, March 2013
