How-To: Find your Windows XP Product Key on the Windows XP CD
I have only tried it on a XP Professional CD, but it should work for the Home and OEM versions of Windows XP from restore disks.
How-To: Find Windows XP Product Key from the Windows XP CD:
1) Insert Windows XP cd into a working computer.
2) Exit the Autorun introduction.
3) Open “My Computer”
4) Right Click on the Windows XP cd-rom drive and select explore.
5) Open the USWXP32P_ZX folder. (It may be as a hidden folder. If you cannot locate the folder, you may also search for unattend.txt and mark “Search Hidden Files”.)
6) Open the sysprep folder.
7) Open unattend.txt
Your CD’s product key is contained within the unattend.txt file.