How can I install the OS from a USB in single user mode? My Mac (MBP) won't get past 30% on the progress bar at startup. Then after a while it reboots itsef and the same thing happens. I tried to boot in recovery mode, safe mode, reset nvram, and still the same thing happens. I have a Yosemite Install USB and I tried to start from that (held down Option Key and chose the disk), however, the same thing happens, the progress bar gets to 30% and hangs. 

I can start in single user mode, and I have tried fsck and nvram reset there, among other things.

So now I'm wondering if its possible to reinstall the OS while in single user mode. I have mounted the Yosemite Install disk in /Volumes/usb. Any help, or other suggestions appreciated.
It seems there is something seriously wrong with your MBP and I would try to figure out, what it might be. When you boot up in verbose mode (press CMD-V), is there any error message on the screen, before it reboots? Or does it freeze at a certain message?