Public Sub DisableCloseButton(ByVal hwnd As IntPtr)
Dim hMenu As IntPtr
Dim menuItemCount As Integer
hMenu = GetSystemMenu(hwnd, False)
menuItemCount = GetMenuItemCount(hMenu)
Call RemoveMenu(hMenu, menuItemCount - 1, MF_DISABLED Or MF_BYPOSITION)
Call RemoveMenu(hMenu, menuItemCount - 2, MF_DISABLED Or MF_BYPOSITION)
Call DrawMenuBar(hwnd)
End Sub