i've just downloaded the demo of ArmA2. I just started the game right after the installation getting an error message. A library called "D3DX9_41.dll" was missing. So i've downloaded that one, and copied into C:\Windows\system.
After starting the demo again, i got another error message. This time ArmA needed "X3DAudio1_6.dll". So i also downloaded it and copied into the same folder.
Since then, ArmA starts properly, but without any ingame sound. By the way, during installation process i could listen to the background music of ArmA 2.
That's my system:
Core2 Quad 9550
4 GB RAM
Windows Vista Home Premium 64-bit (Service Pack 2)
ATI HD 4870 with 512 MB RAM (Palit/Xpertvision)
Asus P5Q-E (Intel P45)
no additional soundcard
Does anyone know this problem?