If you haven't already done it Howard, try a forced update. You can do this by switching off the box at the mains and then switching back on whilst pressing tha backup button on the box. Keep the backup button pressed until the cycle starts, this will be indicated by all of the lights flashing on, if you have a scart connection, a notice will comeup on the TV screen.
If this solves the switching off problem, then the card should work, providing you've had it initialised.
Rolf