To accept a signal from your Freeview box (rather than, say, to look for a signal arriving into its aerial socket) your TV needs to be set to the correct source. I supect that you've somehow managed to select the wrong source.
Turn your TV on. (i.e. get to the blue screen). Then, still using the SAME remote control, press the 'Source' button. (That's probably marked on your remote control by a rectangle, or oval, with an arrow pointing into it but it might simply be labelled 'SRC' or similar). That should bring up a menu on the screen, which is navigated by pressing the up/down buttons on the remote control and then pressing the 'OK' button. You probably need to select 'Scart', Scart1', 'Scart2' or something similar. Once you've got the correct source your TV should then be able to accept a signal from your Freeview box.