Why doesn't he just reinstall from recovery partition. I doubt the HD went bad so fast. Probably a virus or some garbage.
Virus usually wont get stuck in middle of booting safe mode - it will either bluescreen, error out, or start with viruses or start normal.
You can try recovery partiton but 90% chance the hard drive is failing.
Hard Drives go bad faster than you can possibly imagine.
If its not a physical issue you can try doing a system restore back to a previous day when it worked. If it's a virus it will start working now - If I'm right however you will still have issues or recovery will not work