Google result:
Open Start/Run… and type the command:
regedit and click “OK” (or press ENTER).
Go to HKey_Local_Machine\Software\Microsoft\WindowsNT\Cu rrent Version\WPAEvents,
on the right double click on “oobetimer” and change at least one digit of this value to deactivate windows.
Click “OK” and close the Registry Editor.
Step 2
Open Start/Run… and type the command:
%systemroot%\system32\oobe\msoobe.exe /a and click “OK” (or press ENTER).
This will brin’ up de “Activate Windows” window.
Check de option for “Yes, I want to telephone a customer service representative to activate Windows” and click “Next”
Step 3
Then click “Change Product Key” (don’t enter any information on that screen)
Step 4
Type in the new key and click “Update”
The activate Windows by phone window will reappear at this point, just close it by clickin’ de X in the upper right hand corner
Step 5
Reboot your system and Open Start/Run… and type de command:
%systemroot%\system32\oobe\msoobe.exe /a and click “OK” (or press ENTER).
If you see “Windows is already activated” then everythin’ is OK.