Renault Megane Electrnoic Fault?

Hi, my 03 Megane seems to be having major problems but no one thats looked at it so far is able to solve it. It was running fine until 2 days ago, it was parked up when I got home from work for a few hrs then when it was started again, nothing, just a message saying an electronic fault?? The only recent jobs on it was a replacement bulb on the rear numberplate and bottom arm passenger side,which was done between it running and then not, it locks and unlocks itself apart from the boot that has remained locked throughout? the battery is being drained by something but no idea what? the wipers have come on by themselves occasionaly and sometimes i get the message, Steering Lock fault? All the fuses have been checked, any ideas? Many thanks