A guy rings tech support to report that his computer is faulty.
 
Tech:  "What's the problem?"
User:  "There is smoke coming out of the power supply."
Tech:  "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."
 
Ten 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."
 
Ten 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."
 
One 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."