Light Bulb - Microsoft :)

Q. How many Microsoft support staff does it take to change a light bulb?

A. Four. 

One to ask "What is the registration number of the light bulb?",

one to ask "Have you tried rebooting it?",

another to ask "Have you tried re-installing it?"

and the last one to say "It must be your hardware because the light bulb in our office works fine..."