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 files 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 they are 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 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.