How do you inject dll files?

I've downloaded two injectors so far, namely:
-Valkyrie
-SDInject v2

I try injecting the files by adding or opening the dll file. Like, I open the injector, ass the dll hack like super pistol, and it says its injected. (I do this when A.V.A is opened, but not during gameplay). I wanted to know if I'm doing it all wrong. Or, should I add the injection during gameplay?I don't think there's anything wrong with my computer. It's a recently bought laptop which is Windows 7 64 bit.

Thank You So much!

just download .erl deleter and find a good injector like a : " ava's best injector" so open .erl deleter then open injector and add hacks. so start ava and here you go

Thanks for giving the name of the injector!
But what's a .erl deleter?

---------- Post added at 09:59 AM ---------- Previous post was at 09:42 AM ----------

Okay, the valkyrie injector works, as soon as i log in, the hack is injected and i hear a beep BUT the game closes, and what i mean by closes is it just 'closes' or disappears