Many years ago when I was still a novice in computer, I accidentally disabled userinit.exe from startup thinking that it was a spyware using Autoruns. When I restart my computer, I was unable to login to Windows. Whenever I select the user from the list, it logs in and automatic logs off. I had a really tough time trying to restore userinit.exe back to Windows startup list as it wasn’t easy accessing and editing the registry when Windows is unbootable. Autoruns is much smarter now because when you uncheck userinit.exe from Logon, it will warn you that “disabling or deleting Userinit will prevent users from logging on”.

In the end I managed to fix the problem but I couldn’t exactly remember how I did it because I tried many many ways and I got lucky. Today I found a real solution on how to edit Windows registry key values without booting in Windows. If you have a similar situation as my previous case which requires you to edit the registry without Windows, then here is how to do it.

I currently know of 2 ways to do it. One is the easier way and the other way is a longer and more troublesome way. Both requires booting up the computer using CD.

I will first explain the tougher method on how to access registry without booting in to Windows using UBCD4Win. I’ve previously written a guide on how to create a UBCD4Win CD. Once you have the CD created, just follow the few simple steps below.

1. Boot up computer with UBCD4Win.

2. Once Ultimate Boot CD 4 Windows is fully loaded, click Start > Programs > Registry Tools > RegEdit

3. Select HKEY_USERS

4. Click File from menu bar and select Load Hive

5. Browse to C:\Windows\System32\Config\ and select SOFTWARE. Make sure that it is C:\ and not X:\ drive, otherwise you’ll be loading the CD’s registry.

6. Enter the Key Name as NEWHIVE.

7. Expand HKEY_USERS and you’ll see a newly created NEWHIVE in the list. Expand the NEWHIVE and locate the following location.
HKEY_USERS > NEWHIVE > Microsoft > Windows NT > CurrentVersion > Winlogon

8. Double-click Userinit and set it’s value correctly such as C:\Windows\System32\Userinit.exe,

Important Note: Make sure you include the comma at the end after Userinit.exe. It is there by default.

9. Go back to HKEY_USERS and select NEWHIVE.

10. Click File from menu bar and select Unload Hive. Click Yes when asked if you are sure you want to unload the current key and all of its subkeys.

If you already have UBCD4Win created, the whole process is much faster. However, I understand that not everyone has Windows XP disc on hand. So here’s another great free tool called PC Regedit which lets you create, delete and edit Windows registry key-values without Windows.

1. Download PC Regedit

2. Burn the downloaded PCRegedit.iso to a disc. Refer to this guide on how to burn ISO images on a CD.

3. Boot up the computer with the PC Regedit disc and it will load up ISOLINUX 3.11.

4. When everything is loaded, you will see a MyFileChoose Title window. By default you are at config folder. Scroll down a little, select SOFTWARE and click OK.

5. Navigate to root > Microsoft > Windows NT > CurrentVersion > Winlogon.

6. Look for Userinit key and make sure that the value is set as C:\Windows\System32\Userinit.exe, If the Userinit key is not there, you can add a new key by right clicking at the right pane and select Add Key.

You can use this method to load up other registry files and edit them. Here are the explanation of the 5 registry files for HKEY_LOCAL_MACHINE.

Registry Location: HKEY_LOCAL_MACHINE\SOFTWARE
File: SOFTWARE
Backup: SOFTWARE.LOG

Registry Location: HKEY_LOCAL_MACHINE\SECURITY
File: SECURITY
Backup: SECURITY.LOG

Registry Location: HKEY_LOCAL_MACHINE\SYSTEM
File: SYSTEM
Backup: SYSTEM.LOG

Registry Location: HKEY_LOCAL_MACHINE\SAM
File: SAM
Backup: SAM.LOG

Registry Location: HKEY_CURRENT_USER
File: NTUSER.DAT
Backup: ntuser.dat.LOG

Registry Location: HKEY_USERS\.DEFAULT
File: DEFAULT
Backup: DEFAULT.LOG

On Windows-NT based systems such as Windows NT, 2000, XP and Vista, each user’s settings are stored in their own files called NTUSER.DAT and USRCLASS.DAT inside their own Documents and Settings subfolder (or their own Users subfolder in Windows Vista). For example, C:\Documents and Settings\Raymond\NTUSER.DAT.

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