Windows Vista can be activated without a product key when you edit the Windows Vista registry. You can bypass the need to provide a product key by editing certain registry values. This will allow you to postpone activation for an additional 30 days. You can continue to test a version of Windows Vista, recover saved files or gain additional time to find a misplaced product key for a standard activation at a later time.
Click the "Start" button.
Select "Search Files and Folders" and type " Regedit" into the box.
Press the "Enter" key to launch the Registry Editor.
Find the "HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows NT \ CurrentVersion \ SL" registry key.
Right-click on the registry key named "SkipRearm" and choose "Edit."
Type "00000001" as the new Dword value.
Choose "Save" to save the change to your registry.
Close the Registry Editor.
Press the "Start" button.
Type "cmd" in the "Search Files and Folders" section.
Type "slmgr-rearm" at the command prompt and press the "Enter" key.
Reboot your PC to commit the registry change.
This technique can be used to postpone the activation deadline one year or longer. To extend the activation deadline of Vista indefinitely, repeat these steps as necessary. You can use a default value of "00000000" for the Dword.
This is a temporary solution to activating your Windows Vista without a product key. A valid product key must be provided and activated for a legal copy. You must rearm the system again 29 or 30 days later. Any changes in the Windows Registry should be made with caution. Provide the administrator password to approve a User Account Control prompt.