This is not my own, but I have used this disk to reset passwords on ms products:
***************************************************************************
* *
* Windows NT/2k/XP/Vista Change Password / Registry Editor / Boot CD *
* *
* (c) 1998-2008 Petter Nordahl-Hagen. Distributed under GNU GPL v2 *
* *
* DISCLAIMER: THIS SOFTWARE COMES WITH ABSOLUTELY NO WARRANTIES! *
* THE AUTHOR CAN NOT BE HELD RESPONSIBLE FOR ANY DAMAGE *
* CAUSED BY THE (MIS)USE OF THIS SOFTWARE *
* *
* More info at: http://home.eunet.no/~pnordahl/ntpasswd/ *
* Email : pnordahl@eunet.no *
***************************************************************************
Just boot this CD and follow instructions.
Usually, just pressing return/enter should work, except some
drivers (ISA for instance) may have to be loaded manually with
the 'm' menu option after boot.
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The password reset and registry edit has now been tested with the following:
NT 3.51, NT 4, Windows 2000, Windows XP, Windows 2003 Server,
Vista and Server 2008.
As far as I know, it will work with all Service Packs (SP) and
all editions (Proffesional, Server, Home etc)
Also, 64 bit windows version (XP, 2003, Vista, 2008) shold be OK.
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here is a url where you can download this utility:
http://www.petri.co.il/forgot_administrator_password.htm#1