How to Make Windows XP Genuine:
# Deactivate Windows
1. Click Start, and then click Run.
2. In the Open box, type regedit, and then click OK.
3. In the navigation pane, locate and then click the following registry key:
HKEY_LOCAL_MACHINE\Software\Microsoft\WindowsNT\Current Version\WPAEvents
4. In the topic pane, right-click OOBETimer, and then click Modify.
5. Change at least one digit of this value to deactivate Windows.