1, enter grub interface
1, 1 real machine (Linux is not installed on the virtual machine)
Boot screen just came out quickly press the shift key, you can enter the grub interface
1, 2, virtual machine
When open the virtual machine to quickly use the mouse to click on the virtual machine interface, let the mouse into a virtual machine (see the mouse icon), and press the shift key quickly once or twice, you can go in grub interface (if it did not enter shutdown try again)

2, through the keyboard key, the selected ubuntu advanced options, press enter (enter)

3, through the keyboard key, the selected version with recovery mode on the back of the highest option, press the enter key (enter)

4, through the keyboard key, select the root - the Drop to root shell prompt, press the enter key (enter), will be as root into the command line mode

5, and then to mount the hard disk, with read/write mode, the command is
The mount -o remount, rw/

6, type the following command
Passwd username and press the enter key (enter)
After will prompt you to enter a new password, the password is not displayed, but the system can be detected after the input, press enter (enter)
Then it will prompt you to enter a new password again, confirm password, input, press the enter key (enter)

If the above tip: after the update password successful, then the password will modify completed

7, restart the computer with the following command
Reboot, press the enter key (enter)

Eight, after system into the login page, enter the new password login is successful,