Hello Allie0518,
I see from your post that Disk Utility is unable to repair your disk. As the message says, you will need to reformat your hard drive and then restore from a back up. For help with reformatting and restoring, please see the information below. Please note that reformatting your drive will erase everything on it. Before continuing you should confirm that you have a good backup to restore from.
Important: Before you erase and reinstall, back up your important files. If you’re using a MacBook, MacBook Air, or MacBook Pro, make sure the power adapter is connected and plugged in while performing these steps.
You can use these steps to erase the files on your startup disk and install a new copy of OS X:
- Before you begin, make sure your Mac is connected to the Internet.
- Restart your Mac. Immediately hold down the Command (⌘) and R keys after you hear the startup sound to start up in OS X Recovery.
- When the Recovery window appears, select Disk Utility then click Continue.
- Select the indented volume name of your startup disk from the left side of the Disk Utility window, then click the Erase tab.
- If you want to securely erase the drive, click Security Options. Select an erase method, then click OK.
- From the Format pop-up menu, select Mac OS Extended (Journaled). Type a name for your disk, then click Erase.
- After the drive is erased, close the Disk Utility window.
- If you’re not connected to the Internet, choose a network from the Wi-Fi menu.
- Select the option to Reinstall OS X.
- Click Continue and follow the onscreen instructions to reinstall OS X.
How to reinstall OS X on your Mac - Apple Support
OS X: About OS X Recovery - Apple Support
Take care.