Recently, One of my laptop went into infinite reboot loop after Vista autoupdate installed some downloaded updates. I tried a couple of things, such as booting in safe mode, tried the start up repair utility that comes with the Vista DVD startup disk. But none of these works, and my laptop keeps rebooting itself when it's about to get to the login screen. It keeps showing the "Configuring Updates Stage 3 of 3 0% Complete" message. I know using the Vista DVD to perform a system restore to a certain restore point before the last autoupdate date will certainly work, but what about people who have never created any system restore points. Well, here is a better solution that I find from softpedia that works. So, I am sharing this with anyone who might have this annoying problem.

1. Insert your Vista Media into your dirve and boot from it.
2. Select "Repair your Computer" from the list.
3. Select "Command Prompt" from the recovery choices.
4. At the command prompt change your directory to C:/Windows/WinSxS
5. Type: del pending.xml
6. Exit and reboot

This will fix all Windows update reboot loops and does not require you to restore your PC to an earlier state.