Transfer Your Registration When Reinstalling Windows XP

It is possible to transfer your Windows XP registration if you need to reinstall your operating system for any reason, this will mean that you will not have to go through the activation process at all. As long as you don't make any hardware changes, take these steps to make it happen:

1. Double-click My Computer
2. Double-click on the "C" drive
3. Go to the C:\Windows\System32 folder (you may have to click on the link that says "Show The contents of this folder")
4. Find the files "wpa.dbl" and "wpa.bak" and copy them to a safe location. You can copy them on a floppy drive or burn it onto a CD or DVD.
5. After you have reinstalled Windows XP on your reformatted hard drive, click "No" when asked if you want to go ahead and go through the activation process
6. Reboot your computer into SafeMode (you can either press F8 as Windows is booting up to see the Windows Advanced Options menu and select SAFEBOOT_OPTION=Minimal or follow the instructions in Starting Windows XP in SafeMode
7. Double-click My Computer
8. Double-click on the "C" drive
9. Go to the C:\Windows\System32 folder (you may have to click on the link that says "Show The contents of this folder")
10. Find the file "wpa.dbl" and "wpa.bak" (if it exists) and rename them to "wpadbl.new" and "wpabak.new"
11. Copy your original "wpa.dbl" and "wpa.bak" files from your floppy disk, CD or DVD into the C:\Windows\System32 folder
12. Restart your system (if you followed the directions in Starting Windows XP in SafeMode you may need to go back into MSCONFIG to turn off booting into SafeMode) From Transferring Windows XP Activation Information
    

credit:http://www.tipsdr.com/windows-xp-activation.html