problem with Toshiba DVR19DTKB2?

I have a Toshiba DVR19DTKB2 and am having problems viewing freeview although I can view video and dvd. It seems as if it is not recognising the freeview channels and it won't even allow me to do another channel search. By unplugging the aerial from the dvd when the tv is on, it loses the picture so I know that wiring is okay. It seems to be something in the setup which is confusing me because it won't let me auto or manual search. It was all working before my mother used the remote and there's nothing in the manual. On the DVR display it is showing 90 but cannot change this unless watch a video but it always returns