This guy calls in to complain that he gets an "Access Denied" message every time he logs in. It turned out he was typing his user name and password in capital letters.
Tech Support: "OK, let's try once more, but use lower case letters." Customer: "Uh, I only have capital letters on my keyboard." A woman called the Canon help desk with a problem with her printer. The tech asked her if she was "running it under Windows." The woman then responded, "No, my desk is next to the door. But that is a good point. The man sitting in the cubicle next to me is under a window, and his is working fine.