Exact position of window after Ok message box button has been pressed

I just subscribed and I would like to submit this simple question/problem on Masm32 :

The following code would when run position a plain grey background only window in a random position upon pressing the Ok button of the message box.

Question/request :

What exact code line should be entered on the provided code below in order to place the window exactly where the user wants it ?

Thanks for your attention

Newbit

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.486
.model flat, stdcall
option casemap:none

includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\user32.lib
includelib \masm32\lib\gdi32.lib

include \masm32\include\windows.inc
include \masm32\include\kernel32.inc
include \masm32\include\user32.inc
include \masm32\include\gdi32.inc
WinMain PROTO STDCALL   :DWORD, :DWORD, :DWORD, :DWORD
WndProc PROTO STDCALL   :DWORD, :DWORD, :DWORD, :DWORD
.data?
hInstance       dd      ?

.data
ClassName       db      "Simple Window", 0
AppName         db      "Press the OK button to see the random position of the window.", 0

.code
start:

    invoke  GetModuleHandle, NULL
    mov     hInstance, eax
    invoke  WinMain, hInstance, NULL, NULL, SW_SHOWNORMAL
    invoke  ExitProcess, NULL

WinMain proc hInst:HINSTANCE,hPrevInst:HINSTANCE,CmdLine:LPSTR,CmdShow:DWORD
    LOCAL wc:WNDCLASSEX
    LOCAL hwnd:DWORD
    LOCAL msg:MSG
    mov     wc.cbSize,SIZEOF WNDCLASSEX
    mov     wc.style,   CS_HREDRAW or CS_VREDRAW
    mov     wc.lpfnWndProc, OFFSET WndProc
    mov     wc.cbClsExtra,NULL
    mov     wc.cbWndExtra,NULL
    push    hInst
    pop     wc.hInstance
    mov     wc.hbrBackground,COLOR_WINDOW
    mov     wc.lpszMenuName,NULL
    mov     wc.lpszClassName,OFFSET ClassName
    invoke  LoadIcon,NULL,IDI_APPLICATION
    mov     wc.hIcon,   eax
    mov     wc.hIconSm, eax
    invoke  LoadCursor,NULL,IDC_ARROW
    mov     wc.hCursor,eax
    invoke  RegisterClassEx,    addr wc
   
    INVOKE CreateWindowEx,NULL,ADDR ClassName,ADDR AppName,\
           WS_OVERLAPPEDWINDOW-WS_SIZEBOX-WS_MAXIMIZEBOX,CW_USEDEFAULT,\
           CW_USEDEFAULT,500,500,NULL,NULL,\
           hInst,NULL
    mov   hwnd,eax
    invoke ShowWindow, hwnd,SW_SHOWNORMAL
    invoke UpdateWindow, hwnd
    .WHILE TRUE
        invoke GetMessage, ADDR msg,NULL,0,0
        .BREAK .IF (!eax)
                invoke TranslateMessage, ADDR msg
                invoke DispatchMessage, ADDR msg
    .ENDW
    mov     eax,msg.wParam
    ret
WinMain endp

WndProc proc hWnd:DWORD, uMsg:DWORD, wParam:DWORD, lParam:DWORD
mov eax, uMsg
.IF eax==WM_CREATE
    invoke  MessageBox, NULL, ADDR AppName, ADDR AppName, NULL
.ELSEIF eax==WM_DESTROY
    invoke PostQuitMessage, NULL
.ELSE
    invoke DefWindowProc, hWnd, uMsg, wParam, lParam
.ENDIF
ret
WndProc endp
end start

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