Chosen Solution
My Mac ran out of battery one day and when I charged it up again and tried to boot it, it gets stuck on the apple logo. I’ve tried to boot to safe mode to which my computer does not respond and I’ve also tried to reset the NVRAM. I do hear the second chime but after that it goes back to the apple logo and loading bar and remains stuck.
To be doubly sure: Do you have a bootable Thunderbolt, FireWire or USB drive you can plug in? If not you could create one from another system. Can you boot up from the external drive? Or, you could boot your system in Target Mode connected to another Mac via Thunderbolt or FireWire cable. Once connected can you access the HD on your system?
