Did you recently install some software and now when you try and log on to Windows XP it automatically logs you off? Not to fear! One of my customers recently found themselves in such a situation. After some Googling, I found a solution, and I’ve posted it here in full, technician-friendly, step-by-step form.
What you’ll need:

  • A working computer:
    • Your Windows XP CD
      • This CD must have Service Pack 1 or higher on it. If your CD does not have this, please see here for info on slipstreaming your original XP CD with the latest Service Pack. You do not need to burn the new slipstreamed version of XP to fix your computer if you don’t want to. Simply point Bart PE to the directory in which the XP CD is on your hard drive to burn the Bart PE CD.
    • An Internet connection (!)
    • A blank CD
    • A CD burner/writer
  • The non-working computer in question:
    • Drive that accepts CDs must be bootable (if it’s not, you shouldn’t be running Windows XP in the first place!)
    • Access to the computer’s Basic Input Output System (BIOS)
Got everything? Let’s get started!

1.) Prepare the Bart PE Recovery CD

First, you’ll need to download the installer for Bart PE. Some guy named Bart Lagerweij has made a program that creates a bootable CD with a mini version of Windows XP on it. He knows his stuff. To download the latest version from his site, go here. If you’re in a hurry, I have archived Bart PE v3.1.10a right here.
Now that you have Bart PE, install it. After it’s installed, you should get a screen similar to this:

Now, download this plugin, known as RunScanner. Since Bart PE is basically a mini version of Windows XP, it has it’s own registry, but you don’t care about editing that, you want to edit the registry of the unbootable machine! RunScanner will load just that upon the startup of Bart PE so it can be done. To download the latest version from the author’s site, go here. If you’re in a hurry, I have archived RunScanner v10015a right here. For those interested, this program is very tweakable. The author has advanced usage instructions on his website here. Now that you’ve downloaded the plugin, please leave it in .CAB form.
Lastly, right-click and save this file: FixLogOnOffLoop.reg. Yep, that little file right over there will save your computer! Please leave the name and file extension alone. Please save this file in its OWN folder on your Desktop.
UPDATE Nov. 12th, 2007: It seems there’s a virus going around, or something. Copy the userinit.exe file from C:\Windows\system32\ directory to the directory you just made on your Desktop above. Only do this if the normal instructions don’t work.
Now that all of that is done, let’s get back to Bart PE.
Pop in your Windows XP CD, close the autorun screen if it pops up, and set the first option to the drive letter that contains your Windows XP CD. Mine in this case, is U:. Next, point the second option to that directory you saved FixLogOnOffLoop.reg to. Mine in this case is C:\Documents and Settings\Wolf\Desktop\PE.

Next, hit F4, or go to Builder -> Plugins. A screen like the one below should come up:

Select Add, then find and select it. Scroll down the list and see if it’s there. Also, make sure it’s enabled. After it’s all been checked out, click Close. Set it to burn a CD with CD-Record using your CD burner/writer by clicking Build. Depending on how fast your burner — and your computer in general — is, it should be done in a matter of minutes.
Now that the CD is burnt, it’s time to go over to the computer that is not booting, and fix it up!

2.) Using Bart PE

Set up your BIOS to boot to a CD drive, or better yet, try and see if your BIOS supports the selection of the boot device with a special key press (sometimes F8, F10, or F12). Worst case scenario is that you’ll have to set your BIOS to boot back to your hard drive when you’re done with the CD. Now, boot up Bart PE. When it’s done loading, you’ll see a dialog box asking for network support. Answer No. You’ll also see a minimized DOS box sitting next to the GO button. This is RunScanner. Let it load, and then when it disappears, you can start.
Go to GO -> Programs -> System Tools -> Remote RegEdit.

Once Regedit opens, go to File -> Import….

Bart PE should drop you in the root of the CD, which would be labeled X:. Select FixLogOnOffLoop.reg, and let it merge.

UPDATE Nov. 12th, 2007: Copy and paste the userinit.exe file using the A43 File Management Utility. Only do this if the normal instructions don’t work.
You should be good to go! Exit Regedit, and restart your computer through the GO button. Eject the CD, and with some luck, you should be able to log in to Windows XP without a problem! Good luck!
~Dan Fischbach
Special thanks to:
Bart Lagerweij