Hi weiji, you can install the same one purchased MoI license on any number of machines you use, including across Windows and Mac, just as long as it is only actively launched and running on one of those installs at a time. You would only need a separate license for another machine if you wanted someone else to be running it there the same time as you.

You don't need to do anything special to set up the multiple installs, you just use the same installer and license key on each one. MoI does not bind itself to only install on one hardware signature, or require any "activation".

> can I use it with a laptop in school and a desktop computer at home?

Yes.

> If my computer is broken, the serial number can continue to be used？

Yes you can just put it on a new machine, you don't have to remove it from the old machine.

> Is a serial number common to PC and MAC?

Yes Windows and Mac use the same license keys.

> In short, what are the restrictions on the serial number?

Just that you don't give it to someone else. It's meant to be used by you and you can use it on whatever machines you use. It does do a check on the local area network to see if any other computers are actively running with the same license key, you will get a "license in use" error in that case. Just exit MoI (close the running program, not uninstall) from the other machine.

- Michael