Right now if you use Steam it automatically updates to 1.62 which means you can't play Takistan Life, here is why: http://tlr.enjin.com/home/m/3767668/article/909342
Crash on loadup/screen
This is most likely due to Battleye. You need version 1.60, if you have 1.61 It will not work.
Download the first one at the top "BE Client for Windows (32-bit)"
If first doesn't work, try this: ...\arma 2 operation arrowhead\Expansion\BattlEye and replace the BEClient.dll with https://rapidshare.com/files/10941678/BEClient.zip
Last one to try if first and second don't work: http://dayzmod.com/forum/index.php?/topic/32290-arma-2-oa-has-stopped-working-crash-to-desktop-fixed/
Note: Steam users must remove set launch options
If those don't work and you still get "Arma2: Reinforcments stopped responding" go into AppData/local and delete the Arma folders and then run it. - Thanks to Riquelmeae.
Note: If you don't know how to get to appdata type %appdata% at the top of the address bar in any folder.
Here is how to downgrade 1.61 to 1.60: http://pastebin.com/gL2BrdrS - Thanks to Tiberion.
If you get "3D/Direct graphical error" it is because you are not changing the beta.exe for the original Arma2OA.exe
If you aren't using the original Arma2OA.exe then it will not work.
Take a look at this:
Also note: FOV problems.
Thanks to The771Project