How to edit Registry from another OS Boot up

Question

I accidentally changed one parameter in Windows and it was crashed and restarted everytime I logon. I can't go with safe mode. Restoring to Known Good Configurations doesn't work too.

Unfortunately I don't have system backup. Are there any ways to recover or edit the registry file from another OS or bootable Windows PE? Which tools can I use to edit?

Many thanks!

Answer 1

Another install of Windows or WinPE would work fine. Once it's booted, go to the command prompt and do something like this:

reg load hklm\Old_System C:\Windows\System32\Config\System
reg load hklm\Old_Software C:\Windows\System32\Config\Software

if you need your user settings:

reg load hku\Old_User C:\Users\Jack\ntuser.dat

The registries can them be edited with RegEdit, note the slightly different names (HKLM\Old_System instead of HKLM\System). When you're done, unload them like this:

reg unload hklm\Old_System
reg unload hklm\Old_Software
reg unload hku\Old-User

Answer 2

Chris S's answer looks like the best method. If you can't go the WinPE route then there's a tool called ntpasswd. It's a bootable CD used to recover forgotten passwords but it can also be used to edit the Windows registry.

Download the bootdisk here:

http://pogostick.net/~pnh/ntpasswd/bootdisk.html

And here's a guide on how to use ntpasswd's registry editor:

http://pogostick.net/~pnh/ntpasswd/regedit.txt