What is wrong with my Renault laguna 1998 when you turn the key and everything goes dead or turn the key and the starter motor just clicks and wont start and sometimes it will?

Sounds like bad battery connections, clean and tighten them and try again. Have the battery checked if no luck ++ Loose connections ++ This just happened to my laguna. The two connections giving power to the starter motor were loose. Couple of quick turns and it fired up first time. Took an hour to get to it as it's buried deep in the engine.