Private Sub btnEnviar_Click()
Dim iFile As Long

Dim ws As Worksheet
Set ws = Worksheets(1)

iFile = ws.Cells(Rows.Count, 1).End(xlUp).Offset(1, 0).Row

If Trim(Me.txtNombre.Value) = "" Then
Me.txtNombre.SetFocus
MsgBox "Debe agregar un nombre"
Exit Sub
End If

If Trim(Me.txtEmail.Value) = "" Then
Me.txtEmail.SetFocus
MsgBox "Debe agregar un email"
Exit Sub
End If

ws.Cells(iFile, 1).Value = Me.txtNombre.Value
ws.Cells(iFile, 2).Value = Me.txtEmpresa.Value
ws.Cells(iFile, 3).Value = Me.txtEmail.Value
ws.Cells(iFile, 4).Value = Me.txtTelefono.Value
ws.Cells(iFile, 5).Value = Me.txtPoblacion.Value
ws.Cells(iFile, 6).Value = Me.cbPais.Value
ws.Cells(iFile, 7).Value = Me.txtMensaje.Value

Me.txtNombre = ""
Me.txtEmpresa = ""
Me.txtEmail = ""
Me.txtTelefono = ""
Me.txtPoblacion = ""
Me.cbPais = ""
Me.txtMensaje = ""
End Sub