I’m getting reading for a webcast, so I’ll blog this quickly — Jeff over at the Coding Horror has blogged how to extend the Vista Grace period.

All the details are in his post “Extending The Windows Vista Grace Period to 120 Days” and a snippet is below:

If you’re on the fence about the impending release of Windows Vista, I recommend trying before you buy. 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.* This probably isn’t news to anyone.

What may be news to you, however, is that you can easily extend the 30-day Windows Vista grace period to 120 days. No hacks required. This is an official, supported operation directly from Microsoft.
To extend the grace period another 30 days, simply start a command prompt as Administrator, and issue this command:

slmgr -rearm       Reboot for the change to take effect, and voila, you have 30 more days
 

* Note that this does not apply to the Enterprise edition of Vista, which only allows a 3 day grace period. The enterprise edition has an entirely different activation scheme; it uses a local volume license key server.