Sorry about the spelling. Couldn't fit the whole word.

Anyway, how would you get a batch file to run a command, then never run that section again or delete that section of the batch file.

I'll show you what I mean. This is my batch.

@echo off
Title Sound in firefox
type nul > "C:\Program Files\Mozilla Firefox\a.dll"
echo Push "D" to disable sound in firefox.
echo Push "E" to enable sound in firefox.
echo.
set input=
set /p input=
if %input%==d goto d
if %input%==e goto e
:d
@echo off
cd "C:\WINDOWS\system32"
rename "C:\Program Files\Mozilla Firefox\a.dll" "msacm32.dll"
cls
echo Sound is Disabled.
echo Please restart your Firefox browser.
echo (This is required in order for sound to be disabled)
ping localhost -n 4 >nul
goto end

:e
@echo off
cd "C:\WINDOWS\system32"
rename "C:\Program Files\Mozilla Firefox\msacm32.dll" "a.dll"
cls
echo Sound is Enabled in firefox.
ping localhost -n 2 >nul
goto end

:end
end

The line that says

type nul > "C:\Program Files\Mozilla Firefox\a.dll"

needs to run only once. How do i do that?

Oh and by once I mean the first time I double click it, it runs. The second time I start it, it doesn't run that command.

Never mind I need something else.

I don't get where you're headed but the simple way to run a BAT section only once:

::== my.bat
@echo off > #-#
:: do stuff
if exist #-# goto :second
:: this gets done only on first run
:second
:: do other stuff
================================

Other comments:

No point in turning echo off more than once.

No point changing to a directory then doing a REN in another..

Instead of creating an END, use the built-in :eof

You can simplify the user input and branching to this:
==================
set /p tag=choose D [disable] or E [enable]
goto :%tag%
:D
here's D
:E here's E
=====================

=====================================
If at first you don't succeed, you're about average.

M2