1. Turn your computer on.
2. Press ESC at the grub prompt.
3. Press e for edit.
4. Highlight the line that begins kernel ........., press e
5. Go to the very end of the line, add rw init=/bin/bash
6. press enter, then press b to boot your system.
7. Your system will boot up to a passwordless root shell.
CAUTION: This is a FULL ROOT SHELL! You can damage your system if not careful!
8. Type in passwd <username>. Set your password.
9. Type in reboot.