As a proportion of people who use computers, the amount of ppl who would be gullible enough to format their hard drive is higher than you would expect.
Classic example of ubern00bs is using the cd tray as somewhere to put their drinks.
A friend of mine worked in IT support once and his examples were:
Someone complained that their computer was running a bit slow, my friend advised cleaning the desktop the complainee took that to mean tidy up their actual desk.
While recommending a shut down and restart my friend told the person to switch on the tower. The person's reply was "Tower? oh i though that was a heater to warm my feet."
In some other support request my friend told the person needing help to close all windows and so the person got up from their desk and shut all the windows to the office.
I solemnly swear that the above is all true to the best of my knowledge, i kid you not.