Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" _
(ByVal hwnd As Long, ByVal lpString As String, ByVal cch As Long) As Long

Declare Function GetWindowTextLength Lib "user32" Alias "GetWindowTextLengthA" _
(ByVal hwnd As Long) As Long

Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
(ByVal lpClassName As String, ByVal lpWindowName As String) As Long

Declare Function GetParent Lib "user32" (ByVal hwnd As Long) As Long

Declare Function GetWindow Lib "user32" (ByVal hwnd As Long, ByVal wCmd As Long) As Long

Declare Function GetForegroundWindow Lib "user32" () As Long

Dim FromMyProg As Boolean

Sub MyGetActiveWindow()
  Const GW_HWNDNEXT =  2 
  
  Dim hwnd As Long
  Dim MyStr As String
  
    hwnd = FindWindow(vbNullString, vbNullString)
    Do While hwnd <>  0 
        ' проверяем тока родительские окна
        If GetParent(hwnd) =  0  Then
            MyStr = String(GetWindowTextLength(hwnd) +  1 , Chr$( 0 ))
            GetWindowText hwnd, MyStr, Len(MyStr)
            If InStr(MyStr, "ИмяПрогиКотораяИнтересует") >  0  Then
                ' а вот и окно нашей проги - проверяем, оно активно в данный момент
                If (GetForegroundWindow = hwnd) Then FromMyProg = True
            End If
        End If
        ' пока окна не кончатся
        hwnd = GetWindow(hwnd, GW_HWNDNEXT)
    Loop
End Sub

Sub AutoNew()
    FromMyProg = False
    Call MyGetActiveWindow
End Sub

Sub AutoOpen()
' нафсякей - если открываем уже существующий файл в той же сессии, что и создан объект
    FromMyProg = False
End Sub