My MacBook Pro is stuck on grey loading screen with apple logo and spinning wheel.

Here are a couple of things that won't hurt and may just fix the issue.

First clear NVRAM. Reboot the computer and hold the Command-Option-R-P keys at the boot chime. The screen will light up for a second, go back to black, then light up again. The flashing of the screen lets you know that the memory was cleared.

If the above doesn't help, then boot back into recovery (the same place you repaired your hard drive and permissions). Repair the hd again but when it completes, reinstall the OS. This will not cause you to lose anything. It simply puts a new copy of the OS over the existing copy.

You don't need apple care to reinstall the OS. When you booted into recovey, what was the smart status of your hard drive? Where there any error messages in after doing a repair?

Your hard drive may have failed. If you're seeing a stop sign and a "contact apple care"

You may need to make a genius appointment. There was an update for certain Mac's to be compatible with internet recovery (they were orignally shipped with Lion). It sounds like that update did not happen or your mac was not one of the models. Either way, you will need installation media (DVD, USB).

When you select a drive in disk utility, at the bottom is the SMART status. It lets you know about the drive's health.

That's positive. It sounds like we know you can get into recovery, we know the disk passes disk repair, we know the smart status is verified.

however.....

If safe mode won't boot the computer and normal recovery/internet recovery don't work for a reinstall, then you're gonna need installation media. I don't know of any other way. Maybe someone else does. Sorry I couldn't help but my knowledge is limited.

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