Не создается диалоговое окно

#include <windows.h>
#include <stdlib.h>
#include <conio.h>
LRESULT CALLBACK MainWinProc(HWND,UINT,WPARAM,LPARAM);
#define ID_MYBUTTON      1 
#define IDD_ABOUTBOX     7
INT_PTR CALLBACK    About(HWND, UINT, WPARAM, LPARAM);
 
HWND hMainWnd;
HBITMAP startBitmap;
HINSTANCE hInstance;
int WINAPI WinMain(HINSTANCE hInst,HINSTANCE,LPSTR,int ss) {
 
WNDCLASS wc;
wc.style=0;
wc.lpfnWndProc=MainWinProc;
wc.cbClsExtra=wc.cbWndExtra=0;
wc.hInstance=hInst;
wc.hIcon=LoadIcon(hInst,"ID_ICO");
wc.lpszMenuName="Ex4_Menu";
wc.hCursor=NULL;
wc.hbrBackground=(HBRUSH)(COLOR_WINDOW+1);
wc.lpszClassName="Example 4 MainWnd Class";
if (!RegisterClass(&wc)) return FALSE;
 
hMainWnd=CreateWindow("Example 4 MainWnd Class","Êàðàíäàø",WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInst
,NULL);
if (!hMainWnd) return FALSE;
ShowWindow(hMainWnd,ss);
UpdateWindow(hMainWnd);
 
hInst = hInstance;
 
MSG msg; 
while (GetMessage(&msg,NULL,0,0)) {
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
 
 
LRESULT CALLBACK MainWinProc(HWND hw,UINT msg,WPARAM wp,LPARAM lp) {
switch (msg) {
case WM_CREATE:
CreateWindow("button","My button",WS_CHILD|BS_PUSHBUTTON|WS_VISIBLE,5,5,100,20,hw,(HMENU)ID_MYBUTTON,NULL,NULL);
return 0;
 
case WM_COMMAND:
if (HIWORD(wp)==0) {
char buf[256];
switch (LOWORD(wp)) {
    case 6: 
    PostQuitMessage(0);
    break;
    case 7:
        CreateDialog(hInstance, MAKEINTRESOURCE(IDD_ABOUTBOX), hMainWnd, About); //<<<<<<<< вот сдесь это окно
     wsprintf(buf,"Command code: %d",LOWORD(wp));
    MessageBox(hw,buf,"Ýòî ïðîõîäèò",MB_OK|MB_ICONINFORMATION);
        break;  
    default:
    wsprintf(buf,"Command code: %d",LOWORD(wp));
    MessageBox(hw,buf,"MessageBox",MB_OK|MB_ICONINFORMATION);
}
}
return 0;
case WM_DESTROY:
 
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hw,msg,wp,lp);
}
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        return (INT_PTR)TRUE;
 
    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    }
    return (INT_PTR)FALSE;
}