[Help]DLL inject

Greetings, my code for injecting a dll seems to fail. My injector sometimes just doesn't find notepad++.exe. And when it does it injects, but then Notepad++ crashes. I also tried it with notepad.exe but Notepad doesn't crash OR show the messagebox.
First I tried to add a button to the menu as showed on another site, then I tried to just show a messagebox, both of them caused the results as I stated before.

Here is my injector code:
main.cpp

Code:

#include <cstdio>
#include <windows.h>
#include <tlhelp32.h>

int GetProcessIdByName(char * procName);

int main()
{
	char dllName[] = "NotepadHack.dll";

	printf("DLL Injector\n");
	printf("____________\n");
	printf("\n");
	printf("Openening process notepad++.exe...\n");

	HANDLE hProcess = NULL;
	hProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, GetProcessIdByName("notepad++.exe"));

	if(hProcess == NULL)
	{
		printf("Process could not be opened.\n");
		getchar();
		return 1;
	}
	
	printf("Process opened successfully.\n");

	getchar();

	printf("Injecting DLL...\n");

	LPVOID pLibAddress = GetProcAddress(GetModuleHandle("Kernel32.dll"), "LoadLibraryA");
	LPVOID pDllAddress = VirtualAllocEx(hProcess, NULL, sizeof(dllName), MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
	WriteProcessMemory(hProcess, pDllAddress, dllName, sizeof(dllName), NULL);

	CreateRemoteThread(hProcess, NULL, 0, (LPTHREAD_START_ROUTINE)&pLibAddress, pDllAddress, 0, NULL);

	printf("DLL injected successfully.\n");

	printf("Closing process handle...\n");
	CloseHandle(hProcess);

	getchar();
	return 0;
}


int GetProcessIdByName(char * procName)
{
	PROCESSENTRY32 entry;
	int procID = -1;

	HANDLE hSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);

	if(Process32First(hSnapshot, &entry) == TRUE)
	{
		do
		{
			if(stricmp(entry.szExeFile, procName) == 0)
			{
				procID = entry.th32ProcessID;
			}
		}while(Process32Next(hSnapshot, &entry) == TRUE);
	}

	CloseHandle(hSnapshot);

	return procID;
}

Here my DLL: (I commented out the CreateThread to test whether I could just get the MessageBox working.)
main.cpp

Code:

#include <windows.h>

HWND hWindow = NULL;

BOOL CALLBACK EnumWindowsProc(HWND hWnd, LPARAM lParam)
{
	hWindow = hWnd;
	return TRUE;
}

DWORD WINAPI StopProcess()
{
	MessageBox(NULL, "This should appear", "NotepadHack", 0);

	EnumWindows((WNDENUMPROC)EnumWindowsProc, NULL);
	
	if(hWindow == NULL)
	{
		MessageBox(NULL, "The window was not found.", "NotepadHack", 0);
		return FALSE;
	}
	HMENU hCurrentMenu = GetMenu(hWindow);
	HMENU hNewMenu = CreateMenu();

	AppendMenu(hCurrentMenu, MF_STRING | MF_POPUP, (unsigned int)hNewMenu, "NotepadHack");
	AppendMenu(hNewMenu, MF_STRING, 2000, "Button");
	DrawMenuBar(hWindow);

	return TRUE;
}

BOOL WINAPI DllMain(HINSTANCE hModule,
					DWORD fdwReason,
					LPVOID lpReserved)
{
	switch(fdwReason)
	{
	case DLL_PROCESS_ATTACH:
		{
			//CreateThread(NULL, NULL, (LPTHREAD_START_ROUTINE)&StopProcess, NULL, 0, NULL);
			MessageBox(NULL, "Hello World!", "Hack", 0);
		}break;
	}
	return TRUE;
}

I'm using Windows 7 and I run the injector as Administrator.

do
{
if(strcmp(pe32.szExeFile, "notepad++.exe") == 0)
{
hProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, pe32.th32ProcessID);
break;
}
}
while(Process32Next(hProcessSnap, &pe32));

Originally Posted by Matrix_NEO006

do
{
if(strcmp(pe32.szExeFile, "notepad++.exe") == 0)
{
hProcess = OpenProcess(PROCESS_ALL_ACCESS, FALSE, pe32.th32ProcessID);
break;
}
}
while(Process32Next(hProcessSnap, &pe32));

Thanks for the reply, however I'm opening the process in my main function and I'm using the GetProcessIdByName to return the process ID. And I use OpenProcess to open the process with the process ID provided by GetProcessIdByName. So I don't open it in the GetProcessIdByName.

I also updated the program, I changed int to DWORD since PROCESSENTRY32.th32ProcessID seems to be a DWORD, but it's still not working correctly.

Code:

char dllName[] = "NotepadHack.dll";

the target process cant know where is that file. could be on C:/ or on C:/WINDOWS.. you have write the full path into the targets memory. or the target process wont find the dll. if the dll would be in the target executable directory it would be ok.

Originally Posted by Gordon`

Code:

char dllName[] = "NotepadHack.dll";

the target process cant know where is that file. could be on C:/ or on C:/WINDOWS.. you have write the full path into the targets memory. or the target process wont find the dll. if the dll would be in the target executable directory it would be ok.

The dll is in the the executable's directory