I dont understand your questions, but I am trying to answer it.
You can get the path of the process with GetModuleFileNameA/W.
If you want to find a running process, use Process32First/Process32Next. Process32Next returns a pointer to a struct that contains the process id of the process. You would only need to use this process id with OpenProcess (last parameter). Then you got a process handle. Now you could change the memory of this process with WriteProcessMemory.
I think you are german - PM me what exactly you want in german, so I can give you a better answer.