Use a hardware key instead. That also provides good anti-piracy protection and does not make your customers angry.
Yes, i understand that MPA will cause some problems. But hardware key is also sort of pain . My company's software right now is using hardware key attached to LPT. I got a lot of complain about the key compatible issues with printers. The worst thing is some notebooks even don't have the LPT port, USB port only. From my point of view, it all depends on how critic of the information you collect. I am not going to collect very detail info about the machine. Maybe just the SN of C driver that is hardly changed . Since the users of my software are only small group of people with limited computer knowledge, i think it should work. Anyway, thank you for your suggestion.