Same problem here. Found out a while back, but never really did anything about it. Assumed BI would fix it. How naive.
Anyway, I'm running windows vista 64 bit, 4gb RAM, "Intel Core 2 CPU E8500 @ 3.16ghz".
ArmA2 1.04 worked.. well, decently. I mean, it still feels like a beta, but at least it worked. 1.05 result in a crash right before the menu is supposed to appear. I did the same Event Viewer thingy as Ukez. I got this:
"Faulting application arma2.exe, version 1.5.0.62017, time stamp 0x4b2f54d8, faulting module kernel32.dll, version 6.0.6001.18215, time stamp 0x4995344f, exception code 0xc0000005, fault offset 0x00010e0d, process id 0x10e8, application start time 0x01caa03b81d5d46a."
and
"Faulting application arma2.exe, version 1.5.0.62017, time stamp 0x4b2f54d8, faulting module kernel32.dll, version 6.0.6001.18215, time stamp 0x4995344f, exception code 0xc0000005, fault offset 0x00010e0d, process id 0xc14, application start time 0x01caa03a812390da."
Hope its of any use for both the other people out there not being able to play ArmA2 as myself.
Yay for big posts.