Windows 8 has a very different StartUp repair protocol than Win-7.
If Win-8 can't start, reboot and it will start the Win-RE environment.
Click on the Advanced Repair Options, then Troubleshoot, then Advanced Options, then Windows StartUp Settings. Choose "Repair your Computer" and see if that will correct the problem
Another important landmark to note is what you see on the screen just before it hangs. For example, just after the Splash Screen, After the StartUp config page, just after OS is starting, or just after Starting Windows, or even after the LogOn page. That can help pin down what the problem is.