Как из программы управлять другой, уже запущенной программой

Option Explicit
Private Declare Function GetDesktopWindow Lib "user32" () As Long
Private Declare Function GetWindow Lib "user32" _
   (ByVal hwnd As Long, ByVal wCmd As Long) As Long
   Private Declare Function GetWindowTextLength Lib "user32" _
   Alias "GetWindowTextLengthA" (ByVal hwnd As Long) As Long
   Private Declare Function GetWindowText Lib "user32" _
   Alias "GetWindowTextA" (ByVal hwnd As Long, _
                           ByVal lpString As String, _
                           ByVal cch As Long) As Long
Const GW_HWNDNEXT = 2
Const GW_CHILD = 5
Dim strCaption As String
Dim dummy&
Dim PT As String
   
Private Sub Часы1_Timer()
    Dim i
     Список1.Clear
           Dim strCaption As String
           Dim hwnd&
    hwnd& = GetDesktopWindow()
    hwnd& = GetWindow(hwnd&, GW_CHILD)
          Caption = ""
    Do
    dummy& = GetWindowTextLength(hwnd&)
    If dummy <> 0 Then
            strCaption = String(dummy + 1, " ")
            dummy = GetWindowText(hwnd&, strCaption, dummy + 1)
            If InStr(1, strCaption, "Подтверждение", vbTextCompare) > 0 Then
                 Caption = "Есть окно"
                 exit sub
    '            MsgBox hwnd& & "  -  " & strCaption, 64, ""
            End If
     End If
    hwnd& = GetWindow(hwnd&, GW_HWNDNEXT)
    Loop While hwnd& <> 0
End Sub

Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" ( _
    ByVal hwndParent As Long, _
    ByVal hwndChildAfter As Long, _
    ByVal pszClass As String, _
    ByVal lpszWindow As String) As Long
 
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" ( _
    ByVal lpClassName As String, _
    ByVal lpWindowName As String) As Long
 
Private Const BM_CLICK = &HF5
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" ( _
    ByVal hWnd As Long, _
    ByVal Msg As Long, _
    ByVal wParam As Long, _
    lParam As Any) As Long

Dim NameProg As String
 
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Sub Command1_Click()
 NameProg = "C:\Program Files\Keepsoft\HomeBuh5\HomeBuh5.exe"    ' путь к жертве
ret = Shell(NameProg, vbNormalFocus)
Timer1.Enabled = True
End Sub
 
Private Sub Timer1_Timer()
 
hnd = FindWindow("TFormConfirm", vbNullString) ' ищем окно с паролем
  If hnd > 0 Then
            Timer1.Enabled = False
      SendKeys "12345" ' Тут пароль настоящий!
            Sleep 500
      SendKeys "{TAB}" ' фокус на кнопку
           Sleep 500
      SendKeys "{ENTER}" ' Жмем кнопку ОК
 
 End If
 
End Sub