This document explains how to reset a local password in windows vista with no extra tools.
Step 1: Restart the computer and press f8 before boot.
You should see a boot options menu. It may take a couple of tries to get this right.
Step 2: From the boot options menu
boot into windows RE command prompt.
Step 3: Navigate to the system32 directory.
cd %systemroot%\system32
Step 4: Rename the following files
cp magnify.exe magnify.bak
cp cmd.exe magnify.exe
If prompted select yes to replace magnify.exe
Step 5: Restart the computer.
At the login screen click the ease of access button and select magnifier.
Step 6: Clicking magnifier now opens a command prompt.
Type control userpasswords2 at the prompt. You will have gained graphical access to your User Accounts in the Control Panel.
Step 7: Reset the passwords and log in.
Restart the computer and boot into windows RE command prompt.
ren magnify.bak magnify.exe
If prompted select yes to replace magnify.exe
Step 8: Restart the computer.
You should now be able to log in using your newly reset passwords.
13 Spice ups
msoule
(Mike Soule)
2
Good how to.
Not too be nit picky or shoot you down but mind adding the reference? I believe the original exploit was shown by the offensive security team.
But again good how-to, this also works with 7’s accessibility I believe.
Thanks. I wouldn’t know who to reference. It’s a trick that I learned working while working at circuit city as a firedog a few years ago. I did a search through the how-tos and didn’t see any similar so I thought it might be useful for some. I wrote it all from memory. (so don’t be surprised if I left something out).
P.S. Mind spicing me up if you like it? 
msoule
(Mike Soule)
4
Oh well that makes sense then. haha
Yeah it’s a worth while sploit to know.
You guys may want to check out (and spice up:-) my other how-to on reseting a XP password with just the XP install CD as well.
http://community.spiceworks.com/how_to/show/1198
Other good how to. I will test on Windows 7 enviroment.
this helped a ton but you need a bootable windows installation disk though.
even though this post is old … we still have vista machines in our organisation …