I have constantly spinning circle on my screen. How do I erase and replace a hard drive.

I know you did the SMC Reset however try again with the instructions in the following link. Do the same with resetting the NVRAM.

1. Reset SMC by following the directions applicable to your MacBook Air here ➔ How to Reset SMC. If that does not solve things then-
2. Reset NVRAM/PRAM by following the directions applicable to your MacBook Air here ➔ How to Reset NVRAM/PRAM. If that does not solve things then-
3. Enter ➔ Safe Mode and see if the issue still exists in Safe mode. Log out of Safe Mode and then reboot computer. If that does not solve things then-
4. Finally if none of the above works then you can enter ➔ macOS Recovery Mode and reinstall the macOS and see if that solves it.

Point #4 above, if you need to reinstall the macOS then that is the option.

Axel F.

Can you run First Aid on your drive by following the instructions in this article by Apple ➔ Repair a storage device in Disk Utility on Mac - Apple Support.

Let us know how you do with the above action.

Axel F.

What exactly happened when you used the macOS Recovery mode and attempted to reinstall the macOS?

Axel F.