I have same problem too.
I bought Arma 2 : Combined Operations today in amazon digital downloads
Arma 2 multi work fine, but OA failed.
"Bad CD Key : Invaild CD key"
I use Windows 7 64 bit, installed Arma 2 (1.09), OA (1.59)
---------- Post added at 05:09 PM ---------- Previous post was at 04:47 PM ----------
oh, it's work fine now.
Good thanks.