Lancslad,
The procedure is the same for all makes and models of digibox. Simply take the card out; turn the power off at the socket; hold the ‘backup’ button on the box in; turn the power back on (while still holding the button in). Keep holding the button in and after about 30secs all the lights should light up, if your TV is on you should see a message on the screen telling you that the software is being updated.
Once it has finished put the card back in.