hola lo que tienes que hacer es enumerar los controles de la ventana y cuando encuetras el texto del control es igual al que buscas significa que ya tienes el hwnd del control luego le pudes enviar el mensage click o enter o como al tener &No le puedes enviar el mensate de la letra N los mensage se envian con SendMessage o PostMessage
aca te hice un ejemplo con una funcion para enviar click al algun control de una ventana
en la funcion tienes que poner el caption de la ventana y seguido el caption del control
En un Modulo
Declare Function EnumChildWindows Lib "user32" (ByVal hWndParent As Long, ByVal lpEnumFunc As Long, ByVal lParam As Long) As Long
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 PostMessage Lib "user32" Alias "PostMessageA" (ByVal hWnd As Long, ByVal Msg As Long, wParam As Any, lParam As Any) As Long
Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Const WM_LBUTTONDOWN = &H201
Private Const WM_LBUTTONUP = &H202
Dim lRetValue As Long
Dim ControlText As String
Public Function EnumChildProc(ByVal hWnd As Long, ByVal lParam As Long) As Long
Dim sSave As String
sSave = Space$(GetWindowTextLength(hWnd) + 1)
GetWindowText hWnd, sSave, Len(sSave)
sSave = Left$(sSave, Len(sSave) - 1)
If sSave = ControlText Then
lRetValue = PostMessage(hWnd, WM_LBUTTONDOWN, ByVal CLng(0), ByVal CLng(0))
lRetValue = PostMessage(hWnd, WM_LBUTTONUP, ByVal CLng(0), ByVal CLng(0))
End If
EnumChildProc = 1
End Function
Public Function MensageClick(WindowsCaption As String, ControlCaption As String)
Dim Handle As Long
ControlText = ControlCaption
Handle = FindWindow(vbNullString, WindowsCaption)
If Handle = 0 Then Exit Function
EnumChildWindows Handle, AddressOf EnumChildProc, ByVal 0&
MensageClick = lRetValue
End Function
y en el formulario
Private Sub Command1_Click()
ret = MensageClick("All rights reserved. Lab Asprise! (c) 1998-2004", "&No")
MsgBox "Mensage enviado?: " & CBool(ret)
End Sub
Te recomiendo para aprender de apis te vajes el Api-guide de la web y vas a ver muchos ejemplos sobre el manejo de estas
Saludos