Function IsTopLevelWindow returns True if the window's text is non-blank, the window is visible, and the window has no owner.

Function WindowText uses the GetWindowTextLength and GetWindowText API functions to return the window's text.

' Find the target window and minimize, maximize,
' or restore it.
Private Sub cmdGo_Click()
Dim action As Long
Dim target As String
Dim app_hwnd As Long
Dim wp As WINDOWPLACEMENT

    ' Set the appropriate action.
    If optPlacement(0).Value Then
        ' Minimize.
        action = SW_SHOWMINIMIZED
    ElseIf optPlacement(1).Value Then
        ' Maximize.
        action = SW_SHOWMAXIMIZED
    Else
        ' Restore.
        action = SW_SHOWNORMAL
    End If

    ' Get the first window.
    target = txtTargetName.Text
    app_hwnd = GetWindow(GetDesktopWindow(), GW_CHILD)

    ' Examine the windows.
    Do While app_hwnd <> 0&
        ' See if this is a top level window.
        If IsTopLevelWindow(app_hwnd) Then
            ' See if the window's text has the target in it.
            If InStr(WindowText(app_hwnd), target) > 0 Then
                ' Get the window's current placement.
                wp.length = Len(wp)
                GetWindowPlacement app_hwnd, wp

                ' Perform the action.
                wp.showCmd = action
                SetWindowPlacement app_hwnd, wp
            End If
        End If

        ' Get the next window.
        app_hwnd = GetWindow(app_hwnd, GW_HWNDNEXT)
    Loop
End Sub

' Return True if this is a top level window.
Private Function IsTopLevelWindow(ByVal app_hwnd As Long) _
    As Boolean
    ' Assume the window is not top level.
    IsTopLevelWindow = False

    ' See if the window's text is blank.
    If Len(WindowText(app_hwnd)) = 0 Then Exit Function

    ' See if the window is visible.
    If IsWindowVisible(app_hwnd) = 0 Then Exit Function

    ' See if the window has an owner.
    If GetWindow(app_hwnd, GW_OWNER) <> 0& Then Exit _
        Function

    ' The window has non-blank text, is visible, and has
    ' no owner so it is (probably) a top level window.
    IsTopLevelWindow = True
End Function

' Return the window's text.
Private Function WindowText(ByVal app_hwnd As Long) As _
    String
Dim text_len As Long
Dim window_text As String

    text_len = GetWindowTextLength(app_hwnd)
    window_text = Space$(text_len + 1)

    text_len = GetWindowText(app_hwnd, window_text, _
        text_len + 1)
    WindowText = Left$(window_text, text_len)
End Function