Citroen C5 dashboard warning lights goes on

I have a citreon C5 2003 model ., recently some water went inside the car from the sunroof accidentally. when i open the door of the car, the dashboard light and all the warning lights on the dash board goes on and after starting the car everything keeps stays on and the radio goes off including all the instruments in the dashboard, only the warning lights stays on eventhough the car's engine runs well...after switching off the car and taking the key out and closing the door...the dashboard light and all the warning lights on the dashboard stays on for a while before turning off. Anybody has any idea about the problem and how to solve it ?