Lost user password

My grandson who is sick with pneumonia has forgotten his user password. :-o
He has an Acer Aspire 5050 and is running Linux 7 Gloria.
Can I do something similar to an F8 start and completely reset to original where he can reset his user password?
Suggestions please...

 

Thanks... I tried both and I can change the boot, supervisor and root passwords, but it still opens asking for a user name and password...

 

UPDATE:
I was finally able to change the 'user' password using the following information. It took me more than 15 tries, so keep trying...


Reset Linux User Password

You can reset your password following the next steps:
1.Reboot your computer / Turn your computer on.
2.Hold down the Shift key at the start of the boot process to enable the GNU GRUB boot menu (if it does not show)
3.Press ESC at the GNU GRUB prompt.
4.Press e for edit.
5.Use the Arrow keys to highlight the line that begins with kernel and press the e key.
6.Go to the very end of the line and add rw init=/bin/bash
7.Press Enter and then press b to boot your system.
8.Your system will boot up to a passwordless root shell.
9.Type in passwd yourusername
10.Set your new password.
11.Restart your system.

Thanks and best of luck to whoever has the problem...