Press the ''[Shift]'' key during startup to get the Grub2 menu\\
In the menu that follows, select ''Advanced options for Ubuntu''\\
In the subsequent menu, select the topmost option that has ''Recovery Mode''\\
In the Revovery Menu, select ''Root - Drop to root shell prompt''\\
You will get to a terminal window\\
Type ''mount -o rw,remount /'' to mount the filesystem\\
If you don't know the username, type ''ls /home'' to see the user directory name\\
Then type ''passwd username'' where username is the user you are trying to reset the password for\\
It will ask you **twice** for a new passwd. Type in the passwd.\\
Type ''reboot'' to restart the system. 