How do I activate my legal Windows XP with my genuine product key ?

Glad you fixed your problem.

I already have my genuine product-key, I saved it on paper in several places.

When I try to activate it fails.

When I try Activating over the Phone, the installation ID required to enter in the phone doesnt shows up.

But now I tried safe mode and then devmgmt.msc every thing is OK.

Then I tried regedit and WPAEvents as in https://www.wikihow.com/Activate-Windows-XP.

And then when I try again Activating over the Phone the installation ID shows up and its OK.

I have succeeded at Activating over the Phone.

I dont know neither how nor why... dont ask.

Nevertheless, thanks for your help.

Regards.

Elisabeth

* Moderator note:

Information in this post was posted originally at

https://answers.microsoft.com/en-us/windows/forum/windows_xp-windows_install/lost-my-product-key-to-reinstall-windows-xp-how/5824d99e-7b5d-4b01-a9ea-e3cc79d4f9dc?page=1&messageId=21fe94f1-f546-4436-bde3-1603333e1025

If the system is still running and this is not an OEM machine (HP, Dell, etc.) you can use one of these free utilities to get your Product Key:

(Grabs the product key from the encrypted registry): Follow the instructions on this page: https://www.lifewire.com/how-to-find-the-windows-xp-product-key-2626106

If the computer is an OEM machine, this will not be useful since the key shown will the OEM's volume license and not one you can use. In this case, contact the computer mftr. to purchase recovery media.

If the system is not running and the computer is not an OEM machine (one you built yourself or had built for you), you will need to purchase a full retail copy of whatever version of XP you want.

If you had a retail copy of XP which you have lost and the system is not running so you can't retrieve the Product Key:

If you have lost your XP product Key , the best option is to call Microsoft. Call on Microsoft Licensing Fulfilment Center Toll Free Number (800) 248-0655 Monday through Friday, 6:00 A.M. to 3:00 P.M. Pacific time.

Contact Microsoft page - http://support.microsoft.com/default.aspx?pr=csscontactfind