Q: Startup problems

The spinning globe usually indicates Internet Recovery for OSX. It indicates that OSX cannot boot. If the incorrect partition was chosen to install Windows and/or the disk was accidentally formatted as an MBR disk, OSX will not not boot from an MBR disk, but it will boot from a GPT disk or a GPT+Hybrid MBR disk.

Can you use How to install OS X on an external drive connected to your Mac - Apple Support and install OSX version that was shipped with your Mac, and upgrade it to match the internal disk version? Once you do that, boot from this external disk, using Alt/Option key and then we can diagnose the issues with your internal disk.

Please also install GPT Fdisk on this external disk (https://sourceforge.net/projects/gptfdisk/).