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 a 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 to you think?"

"Ummm - perhaps if we all get out of the car and get back in
again?"