A guy rings tech support to report that his computer is faulty.

     Tech: "What's the problem?"
     User: "There's smoke coming out of the power supply." 
     Tech: "Oh oh.  You'll need a new power supply."
     User: "No, I don't! I just need to change the startup files."
     Tech: "Sir, the power supply is faulty. You'll need to replace it."
     User: "No way! Someone told me that I just needed to change the
     startup and it will fix the problem! All I need is for you to tell me
     the command."

     10 minutes later, the user is still adamant that he is right. The tech
     is frustrated and fed up.

     Tech: "Sorry, sir. We don't normally tell our customers this, but
     there IS an undocumented DOS command that will fix the problem."
     User: "I knew it!"
     Tech: "Just add the line LOAD NOSMOKE.COM at the end of the
     CONFIG.SYS. Let me know how it goes."

     10 minutes later:

     User: "It didn't work. The power supply is still smoking." Tech:
     "Well, what version of DOS are you using?"
     User: "MS-DOS 6.22."
     Tech: "That's your problem there. That version of DOS didn't come with
     NOSMOKE. Contact Microsoft and ask them for a patch that will give you
     the file. Let me know how it goes."

     1 hour later:

     User: "I need a new power supply."
     Tech: "How did you come to that conclusion?"
     User: "Well, I rang Microsoft and told him all about what you said,
     and he started asking questions about the make of power supply."
     Tech: "Then what did he say?"
     User: "He told me that my power supply isn't compatible with NOSMOKE."