I need 25 character product key for windows xp.

If your product key does not work or you cannot activate your Microsoft product, call the Microsoft Product Activation Center at 888-725-1047.
You will be asked if you are at your computer with the activation window open - respond with "YES" your wiil be asked for your activation I D - respond by saying "HELP", the message will repeat, respond by saying "TRANSFER" - continue to respond with "TRANSFER" until you hear "If you wish to talk with a specialist say transfer" again say "TRANSFER". You will then be asked if you have the activation wizard up on your screen - respond with "YES". Finally, you will be transferred to an activation specialist and you can talk to him to resolve your problem.
If you have any additional questions contact me by clicking on the "Add a comment" link located under your problem description on FixYa. Also, if you believe that this information was helpful to you, please return to the FixYa website and rate my response to your question.
Best regards,
Yavacotech