There are four engineers traveling in a car; a mechanical engineer, a chemical engineer, an electrical engineer and a computer engineer. The car breaks down.
"Sounds to me as if the pistons have seized. We'll have to strip down the engine before we can get the car working again", says the mechanical engineer.
"Well", says the chemical engineer, "it sounded to me as if the fuel might be contaminated. I think we should clear out the fuel system."
"I thought it might be an grounding problem", says the electrical engineer, "or maybe a faulty plug lead."
They all turn to the computer engineer who has said nothing and say: "Well, what do you think?"
"Ummm - perhaps if we all get out of the car and get back in again?"