When turning on the ignition there's no power at all in the car, the dashboard isn't lighting up and the car won't turn over.
Looking at the battery the parts connected to the leads seem to be rusty and have a green substance all around them.
The battery terminals where the leads connect to the battery seem to have a greeny blue powdery substance all over them.
The engine doesn't start up very easily and will often not start at all. When it is running it can cut out completely without warning.