Option Explicit

Private Sub Command1_Click()
    Dim strHeader As String
    
    Inet1.OpenURL "http://www.google.co.ve/jojojojo.html"
    DoEvents
    
    strHeader = Mid(Split(Inet1.GetHeader, "HTTP/1.1")(1), 2, 3)
    
    If strHeader = "404" Then
        MsgBox "No existe"
    ElseIf strHeader = "200" Then
        MsgBox "Si existe"
    End If
End Sub

Option Explicit

Private Declare Function URLDownloadToFile Lib "urlmon" Alias "URLDownloadToFileA" (ByVal pCaller As Long, ByVal szURL As String, ByVal szFileName As String, ByVal dwReserved As Long, ByVal lpfnCB As Long) As Long

Private Sub Command1_Click()
    If Descargar("http://localhost/index.php", "C:\hola.php") = True Then
        MsgBox "Se descargo"
    Else
        MsgBox "el archivo no se encunetra"
    End If
End Sub

Private Function Descargar(URL, Destino) As Boolean
    Dim lRet As Long
    
    lRet = URLDownloadToFile(0, URL, Destino, 0, 0)
    
    If lRet = 0 Then
        Descargar = True
    Else
        Descargar = False
    End If
End Function

Option Explicit

Private Sub Command2_Click()
Command1.Enabled = False
SaveSetting "ejemplo", "boton", "habilitado", "0"
End Sub

Private Sub Command3_Click()
Command1.Enabled = True
SaveSetting "ejemplo", "boton", "habilitado", "1"
End Sub

Private Sub Form_Load()
If GetSetting("ejemplo", "boton", "habilitado") = "0" Then
    Command1.Enabled = False
Else
    Command1.Enabled = True
End If
End Sub

private sub Command2_click()
command1.enabled = false
end sub