When evaluating a user's diagnosis, it might be helpful to spend a little time determining that user's abilities to analyze the problem. Nothing frustrates a sophisticated user more than the question "is your monitor plugged in?"

You can save a lot of time for both the user and the help desk technician by evaluating the skill level of the user. I've suffered too many "reinstall Windows" sessions when diagnosing a DSL problem. "Hmmm. I can traceroute three hops away. Besides, this is an Ultra 5. I don't think a Windows reinstall will do much good." (grin)

Besides, if the user knows how to employ certain tools it can make the help desk technician's life much easer.