Renault Megane - Electronic Fault?

Bought an 03 plate Megane 5 days ago. Placed the card in the slot and pressed start..... Great it started, but so did every light, indicator, radio, window wiper, pretty much everything. Service light came on and the famous "Electronic Fault". Pressed stop, to switch off the car and nothing, everything was still on including the engine. Eventually removed the card, got out of the car and tried to lock it, only then did the engine switch off with all the other electric stuff.

Had the car towed to the garage, they can only look at it in 3 days time... :-( They said that they conected it up and even their systems cannot detect whats actually wrong, they just say its a major fault they need to wait for the auto electrician to have a look at it.

Anyone have any ideas, or same experience?

Thanks.