I seem to be seeing a lot of this especially from our newer members, and those who are just beginning to hack so I feel that it would be to the benefit of all to have this thread.
I will occasionally see a comment such as, "how do I extract?". Well to answer that question, most coders who release hacks will put it into a compression file, such as those with the extension .zip or .rar. Most of the hacks though seem to be compressed into a .rar, so to be able to extract them you will need a program called winrar. I strongly suggest this over Winzip, as it can handle both .rar and .zip files, and although it is supposedly a "40 day trial version" I have been using my "trial version" for over a year and a half.
Now some of you may be wondering, Ok so I have the files extracted from the .rar/.zip. Now what?
Well to answer that question hacking is not just as simple as downloading something then playing the game. Oh no, instead you need to download something else. You need an injector. (For those who know acutely what this does don't flame) Well an injector does exactly what it's name implies, it injects the hacks you downloaded into the game. Now although all injectors will tend to perform the same basic task, most have add-ons or updates so I will tell you what you generally need to do for all of them. I will upload the one that I prefer to use but you can find another if you dislike it, such as PerX or Valkyrie.
What do I do now?
To inject the dll generally you would run DCv2.exe (the injector), if you have Vista or W7 run it as Admin. Then click the top-most browse button, labeled "..." and find the hack you downloaded, meaning the .dll file not the .zip or .rar. Then navigate down to the next browse button, also labeled "...", and find your combat arms directory. This is normally CNexon\Combat Arms\
Then in that folder find engine.exe and open it. Then in the box/category thing labeled as Autoinject, tick the box labeled "enable", then click add. Then start combat-arms, preferably from the direct way
and your hack will be automatically injected into the game. At this point most hacks will be different and you should be able to find good instructions in the thread that posted the hack.