[Floridavid]

I use a Midiator serial port midi interface.I have a couple of them and use them with Compaq Presario Laptops. Why does it accept the Dos drivers and work great on some machines and not on other model Presario Laptops? is this because they changed the Bios on certain machines in different years or models? I load all my files and drivers etc. the same and yet, certain laptops won't recognize the interface when I shell out to Dos to run my Dos Program. Any ideas? Thanks, David