Philips DTR220/05 digital freeview reciever not recieving anymore
If the box is still receiving some channels, then the box is probably not at fault.
If you have done the full "First time Installation" rather than search for new channels, then eithe the aerial, connection or signal is likely to be to blame.
There have been several changes with the Freeview service over the last few months, and there will be more in the run up to analogue switch off.
In some cases, channels have moved, and in other cases the service has been switched off for a short period, low power etc.
Check the aerial on a standard analogue signal, if the quality is poor, then this rules out the box.