Screen Control blown by "luna" theme in XP

Please, no arguments as why I would want to do this. I'm too far into the project, it's working beautifully, except for this one little problem. I already know now there are better ways to approach this application, but I don't have the time now.
A dictator application, Survey, single Workbook solution. Key is absolute control of the application windows while the survey is completed. The listed three functions  disable the entire systems menu, including the close, resize and minimize buttons and menu's of Excel, when Windows Classic Theme is present. When Windows XP Luna theme is present, it fails entirely.
I don't know why. and need to know why, or need similar code  that will work with Luna Theme. Changing the Theme is likely to kill the project. I started this 1000 hours ago with zip programming experience. I've read 1000's of pages, and now realize that much better paths should have been taken, BUT, crunch time is here, and in 4 days project lives or dies on this. I don't work in IT,  I'm a medical technician who wrote most of this while learning, in self defense. It was taken out of my hands and presented, and selected as a best solution to a specific problem. Except Luna kills the control necessary to keep the user focused on the task.
Thanks for any clues. I'm dead new here. If I am violating protocol, please direct me on the proper way to submit this. I don't wish to offend.  It's just thatI am so short of time. Thank you.

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'functions, api calls
Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
      (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
 
Declare Function GetSystemMenu Lib "user32" (ByVal hwnd As Long, _
      ByVal bRevert As Integer) As Integer
 
Declare Function DeleteMenu Lib "user32" (ByVal hMenu As Integer, _
      ByVal nPosition As Integer, ByVal wFlags As Integer) As Integer
 
'Subs that kill and restore system window functions with Windows Classic Theme
'=====================================================================
Sub Disable_Control()
    
    Dim X As Integer, hwnd As Long
    hwnd = FindWindow("XLMain", Application.Caption)
 
    For X = 1 To 9
        Call DeleteMenu(GetSystemMenu(hwnd, False), 0, 1024)
    Next X
'kills top right application buttons, and 6 system menu items.
End Sub
'======================================================================
'restores them.
Sub RestoreSystemMenu()
Dim hwnd As Long
    'get the window handle of the Excel application
    hwnd = FindWindow("xlMain", Application.Caption)
    'restore system menu to original state
    hMenu% = GetSystemMenu(hwnd, 1)
End Sub