Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Function GetClassName Lib "user32" Alias "GetClassNameA" (ByVal hwnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long
Private Declare Function ShowWindow Lib "user32" (ByVal hwnd As Long, ByVal nCmdShow As Long) As Long

Private Sub Command1_Click()
    Dim WinWnd As Long, Ret As String, RetVal As Long, lpClassName As String
    'Nombre de la ventana
    Ret = "Nombre de la ventana"
    'Búsca la ventana
    WinWnd = FindWindow(vbNullString, Ret)
    If WinWnd = 0 Then MsgBox "kp2 no la encontré  ...": Exit Sub
    'te la muestra
    ShowWindow WinWnd, 0
    ShowWindow WinWnd, 1    
End Sub