Ok a 5 second timer added to the second message and it will do nothing if both programs are running at the same time. It also should only do the commands once, until either the other program runs or neither program is running. Let me know how this update works.

Code:
on *:start: .timerautogame 0 30 autogame

alias autogame {
  if ($chkprocess(CSGO.exe)) && ($chkprocess(Dayz.exe)) halt
  if ($chkprocess(CSGO.exe)) && (%autogame != csgo) {
    set %autogame csgo
    msg #pball !updatetitle CSGO Comp w/ oBeE
    .timer 1 5 msg #pball !updategame Counter-Strike: Global Offensive
  }
  elseif ($chkprocess(Dayz.exe)) && (%autogame != dayz) {
    set %autogame dayz
    msg #pball !updatetitle #Dayz PVP Elektro
    .timer 1 5 msg #pball !updategame DayZ
  }
  else set %autogame none
}

alias chkprocess {
  .comopen numMirc1 WbemScripting.SWbemLocator
  if ($com(numMirc1)) .comclose numMirc1 $com(numMirc1,ConnectServer,3,dispatch* numMirc2)
  if ($com(numMirc2)) .comclose numMirc2 $com(numMirc2,ExecQuery,3,bstr,SELECT Name FROM Win32_Process WHERE Name = $qt($1-),dispatch* numMirc3)
  if ($com(numMirc3)) {
    var %total $comval(numMirc3,0)
    .comclose numMirc3
    return %total
  }

  :error
  if ($com(numMirc1)) .comclose numMirc1
  if ($com(numMirc2)) .comclose numMirc2
  if ($com(numMirc3)) .comclose numMirc3
  return -1
}

http://scripting.pball.win
My personal site with some scripts I've released.