Restoring a macbook pro 15 inch early 2011 model to factory settings

What to do before selling or giving away your Mac

Also if you the original install disk and did not update the EFI firmware

Computers that can be upgraded to use OS X Internet Recovery - Apple Support

Yu can install the original install DVD and boot from it and format the drive and install from disk.

Hold power command and S , you can also look it up on YouTube which helps me a lot

Koltmama just what do expect the poster to accomplish by booting the single user mode?

How to start up your Mac in single-user or verbose mode - Apple Support