1. Reboot the system, and when you are at the selection prompt(GRUB menu), highlight the line for Linux and press ‘e’.
  2. This will take you to another screen, where you should select the entry that begins with “kernel” and press “e” again….
  3. Append "single" to the end of that line (without the quotes and give space)
  4. If your system requires you to enter your root password to log into single-user mode, then append init=/bin/bash after “single“. Hit “Enter” to save the changes.
  5. Press “b” to boot into Single User mode.
  6. Once the system finishes booting, you will be logged in as root. Use passwd and choose a new password for root.
  7. Type reboot to reboot the system, and you can login with the new password you just selected.
  8. ENTER INTO THE TTY MODE AND ENTER AS ROOT TO GET ALL THE USER NAME with users AND CHANGE THE PASSWORD OF USER WITH passwd “username” (without Quotes) to get the promt to change the password