We had sold a computer system and software to a local company, and were providing them with ongoing support. One day they called, and said the machine wouldn’t boot.
Me: OK, so what does it display on the screen when you first power it on?
Me: No text at all?
Me: OK, is the light on the front of the monitor on?
Me: And the monitor is definitely plugged into the computer?
User: Hang on… [Checks.] Yes, there are two cables coming out of the monitor, one is plugged into the computer, the other is plugged into the power socket.
Me: OK. Can you open up the panel on the front of the monitor, and try turning the brightness and contrast knobs clockwise.
User: OK. [Pause] No change.
Me: When you power the computer on, does it beep at all?
User: Hang on. [Pause] No, no sound at all.
Me: OK, sounds like a power supply failure. We’ll send someone round.
Someone gets picked to go diagnose the problem. He returns and reports what happened: It turned out that there was absolutely nothing wrong with the machine. The problem was that the user had never pushed the power button on the front of the computer, they’d just been powering it on from the wall.
The user explained as follows: “Oh, I saw the button marked ‘POWER’, but I thought that was like the ‘TURBO’ button, and made the machine go faster.”
Well, yes, in a manner of speaking it did.