This tutorial will help you to rest your password……….
when the GRUB is loaded from your Boot Menu select recovery mode……..
It is usually the second option……you can see in the above pic……..
After you select recovery mode and wait for all the boot-up processes to finish, you’ll be presented with a few options.We want the Drop to root shell prompt option so press the Down arrow to get to that option, and then press Enter to select it.
Now you will in the root……..
If u forgot the user name as well then type- ls /home
this will lsit all the users in the system now selest your username from that….
To reset password type- passwd username
in my case my username is ganesh so i will type passwd ganesh
now it will prompt for new password type that then retype the same password once more….
Then type – exit
The above menu will appear once again from that select resume normal boot thats all…
you resetted the password………..