Electrics gone mad & won't start

[rambling_ned]

Today after unlocking the berlingo, the fuel empty light was on, all airbags lights on, engine stop light flashing, odometer blank and car refused to start. whilst trying to get the car to start the headlights decided to come on their own as did the radio.
From what I've gleaned syptoms point to water in the electric some where but I haven't found where so far. Have pulled out the fuse box tray but seems ok.
local dealer suggested disconnecting battery leads and joining the terminals together for 5 seconds as this would re-set the system but there was no change.
All suggestions welcomed as this is looking expensive from where I am sitting.