Password invalid after computer name change

Hi!

I just changed the computer name of an old pc from work with Windows 7 to use it in my home network as a webserver. The problem is that I forgot that I don't have any local administrator password for this (yes, I was warned, but I thought I had one). I was an administrator on the old domain/user, but not a local administrator.

So now it seems I have no way of logging in! Do I really have to reinstall Windows 7 from scratch to be able to access the PC?

Thanks for any tips!
LVL 8
Knut HunstadAsked:
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EMJSRConnect With a Mentor Commented:
I would just download the Trinity Rescue Kit; so far I've been able to reset any local Windows password with this, on any computer running Windows, providing the hard drive was not encrypted.

http://trinityhome.org/Home/index.php?content=TRINITY_RESCUE_KIT____CPR_FOR_YOUR_COMPUTER&front_id=12&lang=en&locale=en

Easiest solution, ever. Just boot it with defaults, and then choose "Windows password resetting".
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Joe Winograd, Fellow&MVEConnect With a Mentor DeveloperCommented:
Hi khun,
I used this recently to reset the admin password on a W7/64-bit system:
http://pogostick.net/~pnh/ntpasswd/

Note these points from the Overview:

This is a utility to reset the password of any user that has a valid local account on your Windows system.
Supports all Windows from NT3.5 to Win7, also 64 bit and also the Server versions (like 2003 and 2008)
You do not need to know the old password to set a new one.
It works offline, that is, you have to shutdown your computer and boot off a CD or USB disk to do the password reset.
Will detect and offer to unlock locked or disabled out user accounts!
There is also a registry editor and other registry utilities that works under linux/unix, and can be used for other things than password editing.

It worked perfectly for me. I burned a CD of it and keep it around in my bag of tricks.

Also, I was on a thread at EE a while ago where I recommended PogoStick, but two other experts had these suggestions:

http://www.howtogeek.com/96805/how-to-reset-your-windows-password-without-an-install-cd/
http://www.top-password.com/knowledge/reset-directory-services-restore-mode-password.html

I haven't tried either of these other two ideas, but am passing them along for your consideration. Regards, Joe
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Darr247Connect With a Mentor Commented:
I recommend using option #4 in Petter Nordahl-Hagen's NTPasswd util to enable the "Administrator" account, which is disabled by default in Win7, and 'blank' that user's password... once you reboot, select Administrator and hit Enter to logon, then you can use the User Accounts applet in Control Panel to change the password on any existing user (don't forget to set a new password for Administrator).


Before logging out, disable the Administrator account again:

click the 'start' orb
type cmd in the search box
hold down Ctrl+Shift and hit Enter
(or right-click the result that appears at the top of the start menu, under Programs (1), and choose Run as administrator)
answer Yes to the UAC prompt
In the command window that opens, run the command
net user administrator /active:no

"The command completed successfully" should appear... then you can reboot and start using the account[s] on which you reset the password[s].
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Knut HunstadAuthor Commented:
I'm sure all suggestions where valid, but I tested Trinity Rescue Kit first and it worked perfectly!

Thank you all!
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