Was your friend using the default Administrator account or was he using another user account? Booting in Safe Mode will make the otherwise invisible Administrator account accessible. If he knows the admin account that should help him reset his actual account password.

Otherwise, since he didn't have any critical data on it, a reformat might be the easiest way out.

I do not provide any 'underground' info/tools on bypassing/cracking system logins due to the fact that I can not verify the user's actual intend.
I am sure you understand.

~TL