To overwrite a Windows 7 password, one can boot from a Ubuntu LiveCD and run chntpw.

Unfortunately, installing chntpw is not so easy:

$ sudo apt-get install chntpw
E: Unable to locate package chntpw
  • Unfortunately I can't comment to @Nicolas Raoul, that's why I post this as a answer. Sorry for this. I have the same problem when trying to install boot-repair. I tried all this, but it still doesn't work. What can I do? – sevku Aug 13 '15 at 12:24

First open the Ubuntu Software Center, in the Edit menu click Software Sources..., and in the window that appears enable universe as seen below:

Ubuntu enable universe

Then run sudo apt-get update.

You should now be able to install chntpw using sudo apt-get install chntpw.

  • Works perfectly – Shautieh Jul 11 '18 at 17:16

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