Moved to Dreambox section as not an intro.
If you have a mobile phone with camera switch it to camera mode. Point the remote at the camera lens, and you should see the infra-red LED flashing on the screen. If you don't see it flashing, the remote is dead.
If you see the LED flashing, unplug the box from the mains. Open the casing (cover) & gently push down on the connectors (ribbons) at the front of the box & make sure none of them are loose.
Then try the remote again.