ARMA II Free + ARMA II Arrow Head ($19 USD) + DayZ does work!! If you download the Free version of ARMA II (and saved $10 instead of buying CO) there is 1 folder and 1 file you must rename. These instructions are based on my experience with ARMA II and steam! ARMA II will not work after you make the changes, so if you want to play ARMA II (Not CO) ever again note the original names of the file and folder! *Before doing anything we must start ARMA II Free, every guide says to so do it first! *Now when you have had ARMA II to the menu screen and closed the game we need to go rename 1 file and 1 folder *Wander off to C:\Program Files\Steam\steamapps\common\ (64bit users remember this is a 32bit app so itll be C:\Program Files (x86)\Steam\steamapps\common for you guys) *Rename arma 2 free folder to arma 2 then go into the folder *Rename ArmA2Free.exe to ArmA2.exe *Continue following the other guides on how to get DayZ working Since you renamed your ARMA II folder, steam won't know where it is, this doesn't matter because when you're in steam click play on ARMA II ArrowHead then select Combined Operations!