CD key changes back when i launch the game! ?

Hi there, i am trying to change my cd key,

i use the cd changer i got in here somewhere - the file is called arma2oa_keychanger_mpgh.net
but whenever i changes the CD key of my game, it changes it back whenever i launches Day z -

anyone know how to fix? i tried darkys cd changer, but same result -?
btw- im on win 8

but why does it change the key back to the original - (mabye steam?)

---------- Post added at 02:25 PM ---------- Previous post was at 02:15 PM ----------

can just confirm that it is steam/ opening OA that changes the key to the original key -

Download Home › DayZ Commander

Settings:


Make sure no launch with steam.

Steam reverts the cd key back to the purchased one and not the one already in. Add a nonsteam game at C:/Programfiles(x86)/Steam/Steamapps/common/arma 2 operation arrowhead/expansions/beta/arma2oa.exe