- Run the command prompt as an administrator, you can do this by starting cmd and pressing CTRL + SHIFT + ENTER.
- Type “slmgr -rearm” and hit return. The activation period will be reset to another 30 days after a reboot.
- To check if this procedure was successful you can type “slmgr -xpr” at the same command prompt after the reboot.
- Open the registry with “regedit” and navigate to the key HKEY_LOCAL_MACHINE \ SOFTWARE \ Microsoft \ Windows NT \ CurrentVersion \ SL
- Right-click the SkipRearm key and choose to modify it.
- Change the value to 1 and close regedit again.
- Start the command prompt as an administrator again and type “slmgr -rearm” again.
- Reboot the pc again and the Vista activation period was again reset to another 30 days.
Note that this can be done eight times.
Once you have successfully completed the above steps, your Windows Vista activation period will have another to 360 days.