In this tutorial below will show how to effectively validate your Windows XP without spending if you want a real, just a few minutes. I also ask those who may have any doubt to give a read in this entry because it has many important information.
1. Go to Start> Run

2. Type regedit and click OK.

3. Inside the regedit, navigate to the key:
HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows NT \ CurrentVersion \ WPAEvents

4. In the right pane, double-click OOBETimer

5. In the window that was open, delete any value and click OK. Close
regedit

6. Go back to Start> Run and this time type
% systemroot% \ system32 \ oobe \ autorun.exe / a

7. In the window that was open, choose Yes, I call ...

8. In the next step, click the Change product key.

9. In the next step, type the CD-Key:

THMPV-77D6F-94376-8HGKG-VRDRQ

and click the Update button

10. After clicking the Update button, the activation wizard will return to the previous window, then click Remind me later and restart Windows.

11. Reset Windows again go to Start> Run and type:
% systemroot% \ system32 \ oobe \ autorun.exe / a

If your windows do not have the folder msoobe, download [here] or [here].

If you want to download this tutorial, click here (Rapidshare) or (Easy Share).

Long live the Original Windows XP operating system most used in the world! Use sparingly.