This one was apparently fixed by Microsoft a while ago but in case you run into something similar it’s helpful. It will work on any problem where an update has hijacked the screen with an “Update in progress” type of message and won’t let you finish booting windows. This fix will clear that bad update.
Problem: You run Windows Update and select your updates. Once they download everything they prompt you to restart your system. You do so, the computer turns off then on again and windows starts to boot until you see a screen saying: “Configuring updates 3 of 3. 0% complete.” No matter how long you wait and no matter how many times you restart the screen does not go away.
Fix: You need to delete the “pending.xml” file. The file has a list of updates and forces windows to install those updates at startup. By deleting the file you delete the list so Windows ignores the updates.

THE FIRST METHOD:

Microsoft has a fix for this problem up on their website (here) and we’ll take a look at that method first.
The Microsoft “fix” basically tells you to use restore points to send your computer back in time. How far back? Well just far enough so that your computer is in a state before the broken updates were downloaded. The closer this date is to the present the better. If you restore too far back you end up with programs that don’t work and have a confused computer.
So how do you restore without being able to boot into windows? Again, there are two methods:
  1. Take your Vista disc and insert it into the computer. Ensure that your booting with the CD and when the disc loads press “R” as soon as you see the option. Invoking this command will launch the repair section of the Windows CD which contains a System Restore program. Just select the closest time to the present and restore to that.
  2. Boot into safe mode.
  3. Click Start, a menu will pop up.
  4. Click Run from the menu. A window will pop up.
  5. Type in: “rstrui.exe” This will launch the system restore utility.
  6. Select the closest restore point to the present.
After the restore is done you will find that you can boot into windows once again! There is one more step that you need to do. Microsoft recommends installing an update to windows update, crazy eh? You can find that update here make sure that you download and install this right away.

THE SECOND METHOD:

Now in case for some reason the restore point solution doesn’t work for you there is a second method. I got this fix from a fellow tech and unlike the recovery points method this one just modifies the “pending.xml” file. What you basically need to do is delete “pending.xml”. It is not a file that can be deleted easily when you don’t have access to Windows. But of course our favorite tool comes in handy again-
Download and install a copy of The Ultimate Boot Disc for Windows it’s a useful tool to have for these and other kinds of windows problems. Boot from the disc and in the menu that pops up choose Ultimate Boot Disc for Windows (or something of the like.) The next step will take a few moments so get some coffee, or alcohol depending on your mood. There! You will see that we have loaded a modified version of Windows! One filled to the brim with cool tech tools!
Select the “Computer” or “My Computer” icon. This will launch a folder with a list of all of your drives. Select the drive that contains your windows installation.
  1. Click on the Windows folder.
  2. Click on the Winsxs folder.
  3. Find the file pending.xml.
  4. Right click>Properties.
  5. Go to the Permissions tab and give yourself full control over the file.
  6. Click Apply.
  7. Delete pending.xml.
Once we delete the “pending.xml” file windows no longer looks to it for instructions to install updates and we are free to boot into windows normally.
The next time you download updates that need to be installed Windows will recreate the pending.xml file with new correct updates and you’ll be good to go. Once you get into Windows don’t forget to download and install the windows update fix, it can be found here.
How to explain this problem to the client:This is caused by a bad update Mr. Customer, you know how Microsoft is (insert bonding laugh here.) I’ve usually seen it affect HP/Compaq AMD based unit mostly and you will now be safe from this error in the future. Hooray!