No harm in giving Microsoft a call to ask there opinion. If in UK, telephone 0844 800 2400.

Change KEY

Changing the Windows XP product key may be necessary if you discover your current key is pirated or illegal but you don't want to reinstall Windows XP to activate your new legal key.

Changes to the registry are made in these steps. Take great care in making only the changes described below.

1. Click on Start and then Run.
2. In the text box in the Run window, type regedit and click OK. This will open the Registry Editor program.
3. Locate the HKEYLOCALMACHINE folder under My Computer and click on the (+) sign next the folder name to expand the folder.
4. Continue to expand folders until you reach the HKEYLOCALMACHINE\Software\Microsoft\WindowsNT\Current Version\WPAEvents registry key.
5. Click on the WPAEvents folder.
6. In the results that appear in the window on the right, locate OOBETimer.
7. Right-click on the OOBETimer entry and choose Modify from the resulting menu.
8. Change at least one digit in the Value data text box and click OK. This will deactivate Windows XP.
9. Click on Start and then Run.
10. In the text box in the Run window, type the following command and click OK.

%systemroot%\system32\oobe\msoobe.exe /a

1. When the Windows Product Activation window appears, choose Yes, I want to telephone a customer service representative to activate Windows and then click Next.
2. Click Change Product Key.
3. Type your new, valid Windows XP product key in the New key text boxes and then click Update.
4. If you're taken back to the previous screen and prompted, choose Remind me later.
5. Restart your PC.

The COA sticker on the side of the computer will give you the proper keycode and will tell you what version of Windows it is for.

If it is a different version than what you are using just now you could reformat your computer using the same windows disc that is on the Coa sticker.

Make sure it is the Windows sticker that is on the computer and not a sticker for Microsoft Office.

XP Home Coa sticker means you have to install XP Home and you would not be able to use it for XP professional.

Key Finder will NOT find any OEM keys. OK for retail but I'm afraid you'll need to borrow a Home version OEM disc and I guess an SP2 one.