Changing the product key for your Windows XP installation involves two steps:
1. Deactivating your current product key
2. Entering a new product key and activating your Windows XP again.
- Click on Start and select Run. In the Run dialogue box, type in regedit (to edit the registry).
- Go to HKEY_LOCAL_MACHINE\Software\Microsoft\WindowsNT\Current Version\WPAEvents
- On the right-hand pane, right click on the binary value ODBETimer and select Modify. You will see a string of numbers and letters.
- Change at least one character or number to any value between A to F or 1 to 9 respectively. Doing this will make your current Windows product key invalid and deactivates your Windows XP installation.
- To reactivate using the new Windows XP product key, type this command in the Run dialogue box: C:\windows\system32\oobe\msoobe.exe /a and hit <<Enter>> (This will start the Windows Product Activation Wizard.)
- Select the option “Yes, I want to telephone a Microsoft Customer Service Representative to activate windows” and click on Next
- In this screen select the option “Change Product Key” , type in the new product key and click on “Update” and exit the screen.
- If you are using Windows XP Professional or Home edition, you will be prompted to activate your Windows again.
If you wish to find out if your current Windows XP installation has been activated or not, use this command in the Run dialogue box: C:\windows\system32\oobe\msoobe.exe /a
If you wish to find out which version (& Service Pack) of Windows XP you are using, type this command in the Run dialogue box: winver and click OK or hit the <<Enter>> key.