How to find product key of an XP CD

Just got this email tip on how to locate the product key from your Windows XP CD. Haven't tried it myself, but if some of you are looking for your XP product key - here's a good place to search:

Find Windows XP Product Key from the Windows XP CD:

1. Insert Windows XP cd into a working computer.
2. Search for unattend.txt
3. Open it. Your CD's product key is contained within the unattend.txt file.