Normally you would have to play it in multiplayer, but this way you can solo without any bandits and also no more connection problems :)
► Arma 2 mod DayZ
http://dayzmod.com
►Single Player Link:
http://www.mediafire.com/?l2998bu5x5uu5w3
1: Extract the "DayZ_SP.Chernarus.pbo" file to C:\Program Files (x86)\Steam\steamapps\common\arma 2 operation arrowhead\Missions (or where ever your Operation Arrowhead folder is located in the Missions folder)
2: Open up the game
3: Select "Single Player" then "Scenarios"