I have two Macbooks, pretty old. One of them is stuck in some endless loop at startup, the spinning wheel appears, and nothing more happens, have had it running, or should I say stuck, like that, for hours.
I have very little experience from Macs, but I noticed you can make a startup disk in System Preferences.
According to the Apple support page, you can use a USB for that, make a live OS X USB.
My question is this: Can I make such a startup USB, on the healthy Macbook and use it to reinstall OS X on the broken one?