Hi Karen,
Yes, uses OR64 means include once "OR64.inc"
Patrice,
This is my Window code:
  $filename "test.exe"
  uses RTL64
  uses corewin
  uses OR64
  '=========
  'MAIN CODE
  '=========
  
  dim cmdline as asciiz ptr, hinst as sys
  @cmdline=GetCommandLine
  hinst=GetModuleHandle 0
  '
 Function WinMain(sys hinst, prevInst, asciiz*cmdline, sys show) as sys
  '=====================================================================
  WndClass wc
  MSG      wm
  sys hwnd, wwd, wht, wtx, wty, tax
  wc.style = CS_HREDRAW or CS_VREDRAW
  wc.lpfnWndProc = @WndProc 
  wc.cbClsExtra = 0
  wc.cbWndExtra = 0    
  wc.hInstance = hinst
  wc.hIcon=LoadIcon 0, IDI_APPLICATION
  wc.hCursor=LoadCursor 0,IDC_ARROW
  wc.hbrBackground = GetStockObject WHITE_BRUSH 
  wc.lpszMenuName =null
  wc.lpszClassName = strptr "Demo"
  RegisterClass (@wc)
 
  Wwd = 800 : Wht = 640
  Tax = GetSystemMetrics SM_CXSCREEN
  Wtx = (Tax - Wwd) /2
  Tax = GetSystemMetrics SM_CYSCREEN
  Wty = (Tax - Wht) /2
 
  hwnd = CreateWindowEx 0,wc.lpszClassName,"OXYGEN BASIC",WS_OVERLAPPEDWINDOW,Wtx,Wty,Wwd,Wht,0,0,hinst,0
  'OR_CreateWindow(IN dword dwExStyle, IN HWND hParent, IN dword dwStyle, IN long x, IN long y, IN long w, IN long h, IN HMENU CtrlID)
  OR_CreateWindow(0, hWnd, WS_POPUP, 0,0,800,640, 0)
  ShowWindow hwnd,SW_SHOW
  UpdateWindow hwnd
  '
  sys bRet
  '
  do while bRet := GetMessage (@wm, 0, 0, 0)
    if bRet = -1 then
      'show an error message
    else
      TranslateMessage @wm
      DispatchMessage @wm
    end if
  wend
  End Function 
  function WndProc ( sys hWnd, wMsg, wParam, lparam ) as sys callback
  '==================================================================
    select wMsg
        
       case WM_DESTROY
          
         PostQuitMessage 0
       case else 
        function=DefWindowProc hWnd,wMsg,wParam,lParam
     end select
        
  end function ' WndProc
  WinMain hinst,0,cmdline,SW_NORMAL
 
After lauching the window I'm getting the error message below. My Pavilion laptop has Windows10 and Intel graphics hardware.