Depends if your laptop was shipped with El Cap. If so, hold CMD + ALT/Option + R on startup to boot into Internet Recovery. It will download & reinstall the original OS that came with your Mac.
Otherwise you'll need to download an El Cap image and reinstall from that.
Depends if your laptop was shipped with El Cap. If so, hold CMD + ALT/Option + R on startup to boot into Internet Recovery. It will download & reinstall the original OS that came with your Mac.
Otherwise you'll need to download an El Cap image and reinstall from that.