Although its always good to buy any software, instead of piracy. No one recommends piracy anyways. But then, Every Vista DVD includes the ability to install any edition of Vista without a product key. When you install without a product key, you get an automatic 30 day evaluation period. So, that’s not a news right. But, then what if, you can use it for more than that, 120 days to be precise. Yeah, that’s true, and ofcourse helpful too. But, then how to do it. That’s why you land in here, right. So here is the solution.
To extend the grace period another 30 days, simply start a command prompt as Administrator, and issue this command:
Reboot for the change to take effect, and voila, you have 30 more days. You can only extend three times, so the total grace period for a Vista evaluation is 120 days.But, still because, no one recommends piracy, so if you are still willing to use Vista after these 120 days of grace period, then kindly go ahead and buy it.