How to install Windows Vista without supplying the product key?

Well, you can, sort of.

You can configure Windows Vista to install without having to manually enter the product key during the setup process. This is quite useful if you find yourself in need to perform an installation of the OS but without having the (legal) product key with you at that very moment. Unlike previous Windows versions where you had to have a CD Key handy during the installation of the OS, the Windows Vista setup process only makes it appear as if you have to enter a product key to install it.

During the setup program's progress you will reach a dialog box that will ask you to enter a valid product key. Here is where the fun part starts. You can actually leave it blank!

Next click No in response to the "Are you sure" dialog box. You will now be presented with a list of all the different Windows Vista versions available on the DVD. Yes, the cool thing about the Windows Vista DVD is that every DVD has every version of Vista available for you to pick from, and the product key you own is the only thing that tells the setup process what version of Vista it should install.

You can now pick any one from that list and use it for up to 14 days without any having any issues. After 14 days you will need to enter a valid product key or do a fresh install from the beginning.

This "feature" will in fact help you if you'd like to test the different versions of Vista before deciding which one to buy.

Nice.