My iMac shows the boot up screen then shuts off and shows an error screen saying it is rebooting then repeats what just happened. I don't know what to do any help would be appreciated.
i need Mac help
iMac, iOS 9
Reinstall OS X. Unfortunately, you haven't provided any helpful information, so this is all I can suggest. Hopefully, you know how to reinstall whatever version of OS X you have installed.