Im having a similar problem or the same i suppose.

Both DayZ and steam bootstrapper goes "Not Responding" when i press something in the menu before entering a game.

Can also happen right after i get loaded into the game, i take 1 step forward and it crashes. But it also seems that ingame i am not removed. As when i finaly manage to get in, i am far away from where i was. Wich i am guessing is because ingame i am still running. This has also beem comfirmed by people i play with. I say im crashed and i keep on running for a long time.

Iam on the latest version as of 01.01.14. But problem has been there since start, just worse over the holidays