This is just the activation crack that allows you to extend out your trial period a little bit longer, up to your maximum period of 120 days if used several times. 

The nice thing about this though is that even if it's put your computer into the "limited functionality" state, you can get out of it and use your Vista demo period a little bit longer.

You can check the amount of days left on your trial period by right clicking Computer and going to properties, and it will show you toward the bottom how many days you have left.

If you haven't been put into limited functionility and you need to extend your trial period, click on Start, type in cmd and either hit Ctrl+Shift+Enter, or right click the CMD icon that shows at the top of the list and click Run as Administrator.  Either way should open up the command prompt in administrative mode.

Now type in slmgr -rearm and hit Enter.

This process might take a while, but it should come up with the following box:

What if i'm already in limited functionality mode?

 If you're already in limited functionality mode, you can still use this method to get out of it, you just have to use it a little differently.

When it brings up Internet Explorer, in the address bar type in C:\windows\system32 and hit Enter.  If UAC is turned in, allow this process and it should then browse to the System32 folder. 

Scroll down and find cmd.exe, right click on it and select Run as Administror, and this should open the command prompt, where you can type in slmgr -rearm and hit Enter just like the regular method.

Either of these methods will require a restart, and should extend your trial period. 

TweakXpert.com does not endorse the use of illegal methods of obtaining the vista software.. please only use this tweak if absolutely necessary.