>nLite can also completely frak up an XP install. One specific instance that we encountered when someone in our office used nLite was the inability for anyone who was not an administrator to use USB devices.
I ran into this exact problem. It took me days (off and on) to figure it out. Strangely, there wasn't any reference to it, so I actually had to figure it out myself -- rare these days, it seems.
The cause is that nLite replaces a couple of windows system files so it can monkey with some of the XP setup features.
The original versions are signed, and the nLite versions are unsigned. Windows won't let non-admin users install hardware, even if the drivers are already on the machine, when the install files are unsigned.
Replace these files with the original MS versions from a clean XP install, and you're good to go.
I hope this helps somebody. It sure would have helped me!