How to Activate Windows Vista Without a Product Key

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.

...
You can bypass the Vista activation process by editing certain registry values.

Find the Registry Key

Step

Click the "Start" button.

Step

Select "Search Files and Folders" and type " Regedit" into the box.

Step

Press the "Enter" key to launch the Registry Editor.

Step

Find the "HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows NT \ CurrentVersion \ SL" registry key.

Edit the Registry Key

Step

Right-click on the registry key named "SkipRearm" and choose "Edit."

Step

Type "00000001" as the new Dword value.

Step

Choose "Save" to save the change to your registry.

Step

Close the Registry Editor.

Rearm Activation Time Limit

Step

Press the "Start" button.

Step

Type "cmd" in the "Search Files and Folders" section.

Step

Type "slmgr-rearm" at the command prompt and press the "Enter" key.

Step

Reboot your PC to commit the registry change.