The answer from Joe won't help because it is based partly on a misunderstanding. (BTW,this box is for Satellite Set Top Boxes. Freeview TVs are DTT Receivers.) However ...
As your Freeview TV used to work and ordinary analogue TV works I suggest that you try to do a Factory Reset. Have a look through the handbook. If you have lost it try pressing Menu on your remote. You are looking for reinstall or similar. Run the reinstall and see what happens. If you need more, post back on a NEW question.
t
November 2007