Hello Cathy, I know this might sound silly but have you checked your cables, if its a scart cable, sometimes they can hang out of the socket of your TV, or from your skybox or freeview box and only give you sound, Check and push the cables back in the sockets to make sure they are all in tight, if this doesnt work, then try another source to show a TV picture, like a DVD player, or video, or video camera, anything that you can connect up to it to show a picture.
Hope this helps you.
Mr Roper
May 2008