Stalk the stalk
Years ago I took a help desk call from a secretary to rectify a problem with a monitor - the system was turned on but there was nothing being displayed on the VDU.
I asked all of the usual questions:
Q: Is you PC turned on; can you see any disc and/or power lights on the front of the box?
Q: Can you see any active lights on the front of the monitor
Q: Can you take a look at the cables for me. Is there a power cable from the wall plugged into the rear of the monitor?
Q: Is there a cable from the back of your PC to the monitor?
Q: Are all of the cables plugged in correctly and turned on?
I then said I'd come over and take a look. It took me a while to get to the other side of the hospital. Upon arrival at the secretary's office I noticed the problem, instantly, and pushed the power cable home in the back of the monitor. I said: "I asked you if you'd checked this cable and you said you had!"
I got the reply: "Oh! Yes! I couldn't be bothered, really. I wanted you to come over and fix it for me!"
"Fine!" I replied, and stalked out of the office muttering under my breath.