From an ex-field-sales/support survivor:

I used to work in a computer store and one day we had a gentleman call in with a smoking power supply. The service rep was having a bit of trouble convincing this guy that he had a hardware problem.

Service Rep: Sir, something has burnt within your power supply.

Customer: I bet that there is some command that I can put into the autoexec.bat that will take care of this.

Service Rep: There is nothing that software can do to help you with this problem.

Customer: I know that there is something that I can put in... some command... maybe it should go into the config.sys.

[After a few minutes of going round and round]

Service Rep: Okay, I am not supposed to tell anyone this but there is a hidden command in some versions of DOS that you can use. I want you to edit your autoexec.bat and add the last line as C:\DOS\NOSMOKE and reboot your computer.

[Customer does this]

Customer: It is still smoking.

Service Rep: I guess you need to call Microsoft and ask them for a patch for the NOSMOKE.EXE.

[The customer then hung up. We thought that we had heard the last of this guy but NO... he calls back four hours later]

Service Rep: Hello, sir, how is your computer?

Customer: I called Microsoft and they said that my power supply is incompatible with their NOSMOKE.EXE and that I need to get a new one. I was wondering when I can have that done and how much it will cost...