Bad serial key. And "0000" key in register.

[Palmirov]

Hello!
Yesterday, I wanted to play ArmA2/OA. I launched it and got the
message: "Bad serial number is given in setup". To tell you the truth,
I played different mods on ArmA 2: DayZ. Project Reality, UNSUNG
etc. But I have never used any cheats or something like that. But, several times I downloaded from different sources NAMALSK mod and map for DayZ, nothing to tell about beta patches.

I tried several methods to correct this situation - doesn't work for
me at all.
Also, in steam's ArmA2/OA library, in option "CD key" writes me that
I need to enter my CD key. So, I lost it even in steam.
Fortunately, I've written down some CD keys in my copybook.
And, many games that have option "CD-Key", lost their keys: ArmA2, Men of War, Iron Front etc.
And again - I never used cheats. I know about all hints with money from them, and of course viruses.

I suppose, that my keys have been stolen. What should I do?

[Pieless Alfred]

I have this problem aswell, I've been unable to play for some time now. I would love to know how to fix the aswell.

[Codes]

SCROLL down to 2nd last comment... Let me know if it works.

[Codes]

http://steamcommunity.com/app/33930/discussions/0/864957183014894921/

[Palmirov]

To tell you the truth, the problem disappeared. I don't know how.

[Pieless Alfred]

Works fine for me now, thanks.