had similar problem with megane scenic 2 04 plate dci,did everything cut out except hazzard lights?
if so [probably main fuseable link blown] battery + post has a large metal fuse not spade type . that goes to terminal next to post ,you can bridge gap in emergency, but it has to be a high rating [like fuse in jump starter]portable unit.it will need replacing as soon as possible if this has blown. hope this helps ta rich
rich may know[hull], July 2009