You can't free DLL to get source code, you can reverse some functions, but it would take a lot of time, and you need knowledge about this. If you see any fixed free DLL, it was probably fixed via Hex edit...
depends on how the devs obfuscated it, if its not obfuscated at all just use ida pro to analyze the code, if it has server sided checks you can use traffic debuggers to check what is it pointing, then you can just find the function and set a break point in it, and so on. I would say that you'd need 1+ with reversing to free a dll badly coded, without checks and packed with vmp (NO VIRTUALIZATION). It is not an easy task to do. Btw if the dll is well coded and virtualized, it'd be easier to unvirtualize it and do something called "Hex patching". If you want to fix a dll that is crashing, make sure that the dll is not virtualized, that it doesen't has any anti debuggers in it, and then start a debug process so you can see exactly where it is crashing, and patch it hex by hex.
no you are not able just to take a dll and get the source for it lol. you can reverse the bits you need. if you are talking about getting a cheat fixed just with the dll learn to reverse
