How to get your Vista RC1 Serial number
First of all you will need a Windows live account - your hotmail account can be used.
2nd : Go here : Vista RC1 Key
* You will be prompted to login using your Live Account
* You will then see a form requiring some of your personal details - fill up the details properly. Make sure you fill a correct email address as you will get your product key at that email address
* Keep filling up the required forms and clicking ‘continue’.
* When all finishes, you should see the download URLs as given above along with the serial number. You will also get the serial number by email.