Im trying to move a pocket pc game i made onto windows and my createwindow function is registering the class, but not making a window. What is wrong with this function.

Code:
bool SimpleWindow(LPCTSTR ClassName,LPCTSTR WindowName,HWND &WindowHwnd,HINSTANCE &hInstance)
	{
	WNDCLASS wc;

	wc.style = 0;
	wc.cbClsExtra=0;
	wc.cbWndExtra=0;
	wc.lpfnWndProc = MainWndProc;
	wc.hInstance = hInstance;
	wc.hbrBackground =(HBRUSH) (COLOR_WINDOW+1);
	wc.hCursor=0;
	wc.hIcon = 0;
	wc.lpszMenuName = 0;	
	wc.lpszClassName = ClassName;
	
	if(RegisterClass(&wc))
		{

		WindowHwnd = CreateWindow(ClassName,WindowName,WS_OVERLAPPEDWINDOW,0,0,320,320,NULL,NULL,hInstance,NULL);

		if(WindowHwnd != 0)
			{
			return 1;
			}
		else
			{
			MessageBox(0,"Window Create Error","B",0);
			return 0;
			}
		}
	else
		{
		MessageBox(0,"Register Class Error","B",0);
		return 0;
		}
	}