Lost Password
Here is how you can use the Live CD to change the administrative password on your machine if you have lost/forgot the current password. Please note that you can usually boot into RecoveryMode and run the passwd command directly.
- Boot the Ubuntu Live CD.
Press Ctrl-Alt-F1
sudo mount /dev/sda1 /mnt
If you created a custom partition layout when installing Ubuntu you have to find your root partition using the fdisk utility. See the section Finding your root partition.
sudo chroot /mnt
You can now use the passwd command to reset a password.
Note: In the mount command, /dev/sda1 will need to be replaced with the partition where the root of the file system resides.