If you encounter the common "Bad serial number given in setup" error on Steam, it is often due to the game looking in the wrong registry folder. You can find community-verified fixes on the Steam Community Forum. ARMA: Gold Edition on Steam
: Control everything from APCs and tanks to helicopters and fighter planes in a world where strategy and squad-play are everything. ARMA: Gold Edition Free Download
: Fight across over 400 square kilometres of highly detailed terrain. If you encounter the common "Bad serial number