Some problem with DirectX code.

#include "Cor_Direct3D9.h"


int Cor_Direct3DRenderer::Cor_InitializeDirect3D9(HWND hwnd, int width, int height, bool fullscreen)
{
	//check and see if Direct3D9 is ok.
	Cor_Direct3D9 = Direct3DCreate9(D3D_SDK_VERSION);

	//If it couldn't work, display MessageBox
	if(Cor_Direct3D9 != D3D_OK)
	{
		MessageBoxA(NULL,"Direct3D Could not be created","Error",MB_OK);
		return 0;
	}
	HRESULT result = Cor_Direct3D9->CheckDeviceType(D3DADAPTER_DEFAULT,D3DDEVTYPE_HAL,D3DFMT_X8R8G8B8,D3DFMT_X8R8G8B8,true);
	if(FAILED(result))
	{
		MessageBoxA(NULL,"The device type could not be created","Error",MB_OK);
		return 0;
	}

	ZeroMemory(&Cor_PresentParams,sizeof(Cor_PresentParams));

	Cor_PresentParams.Windowed = (!fullscreen);
	Cor_PresentParams.BackBufferCount	= 3;
	Cor_PresentParams.SwapEffect = D3DSWAPEFFECT_COPY;
	Cor_PresentParams.BackBufferWidth = width;
	Cor_PresentParams.BackBufferHeight = height;
	Cor_PresentParams.BackBufferFormat = D3DFMT_X8R8G8B8;
	Cor_PresentParams.hDeviceWindow		= hwnd;

	 result = Cor_Direct3D9->CreateDevice(
		D3DADAPTER_DEFAULT,
		D3DDEVTYPE_HAL,
		hwnd,
		D3DCREATE_HARDWARE_VERTEXPROCESSING,
		&Cor_PresentParams,
		&Cor_Direct3DDevice9);

	if(FAILED(result))
	{
		MessageBoxA(NULL,"Could not create the device","Error",MB_OK);
		return 0;
	}

	Cor_Direct3DDevice9->Clear(0,0,D3DCLEAR_TARGET,D3DCOLOR_XRGB(0,0,0),1.0f,0);

	Cor_Direct3DDevice9->GetBackBuffer(0,0,D3DBACKBUFFER_TYPE_MONO,&Cor_BackBuffer);

	return 1;
}

int Cor_Direct3DRenderer::Cor_Sync()
{
	if(Cor_Direct3DDevice9->BeginScene())
	{
		Cor_Direct3DDevice9->EndScene();
	}

	Cor_Direct3DDevice9->Present(NULL,NULL,NULL,NULL);

	return 1;
}