Yes, an external power supply is included. It is a Native Instruments product with 15 volts DC and 40 watts output

Hello Rafael That's no problem, you can download the software for Mac and Windows and install it as often as you like (on different devices). For me, the software runs on 2 MacBooks and, for fun, also on a Windows desktop. (Just by the way, I wouldn't recommend Windows though, that's definitely Mac territory ;-) )

You can use it with Traktor Pro 3 but not with Traktor Pro 2.

YES, the software is included. https://www.native-instruments.com/de/products/traktor/dj-controllers/traktor-kontrol-s4/