For whatever reason, you obtained a copy of Windows Vista without the license key, here is what you can do to use that unlicensed OS for a year.
When you install Vista, you actually get 30 days of trial before the OS requires you for a license key. Failure to key in the correct serial will lock the OS down till you entered the right key. With a simple fix, you can reset the 30 days trial up to eight times.
- Open a command line window in Administrative mode
- Type slmgr -rearm.
This starts the 30-day countdown anew, no matter how much time is left on your first countdown. You can do this three times (for 120 days total) before it won’t work any more.To get another 240 days of free usage, you have to make a registry tweak.
- Type regedit in the Start menu search box and press Enter
- Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsNT\SL.
- In the right pane, right click SkipRearm and click Modify. Change the 0 to a 1.
You should now be able to do the rearm trick above eight more times.
This trick works for now. There could be a chance that Microsoft will disable this feature in the future to prevent exploitation. Meanwhile, enjoy!