I am unable to boot my mac in El Capitan and Single User mode
Yes. Single user mode is the most basic thing your OS can do. If that fails, you either have a major hardware problem or the OS needs to be reinstalled. 

Most people make a backup and then attempt a reinstall. If you can't reinstall the OS, that pins the problem on the hardware pretty squarely. If it works, you can safely assume the software just needed to be reinstalled.