Some of the methods can be specifically use for certain Windows version. You may need to try each of the methods.
Method 1
1. Insert the Windows XP installation disc.
2. Open My Computer
3. Right click on your CD/DVD drive & click “Open in new windows”
4. Search for unattend.txt.
6. Open unattend.txt using notepad and scroll down to the bottom for the product key.
Method 2
Use this software to find Windows XP product key.
Description
ProduKey is a small utility that displays the ProductID and the CD-Key of Microsoft Office (Microsoft Office 2003, Microsoft Office 2007), Windows (Including Windows 7 and Windows Vista), Exchange Server, and SQL Server installed on your computer. You can view this information for your current running operating system, or for another operating system/computer – by using command-line options. This utility can be useful if you lost the product key of your Windows/Office, and you want to reinstall it on your computer.
Go to this link:
http://www.nirsoft.net/utils/product_cd_key_viewer.html
Method 3
Use Magical Jelly Bean keyfinder software! Head to their website and download software.
Method 4
Find the product key using Speccy software.
