If you are trying out Windows Vista RC2 or any other Beta version of Windows Vista, you have 30 days to Activate the Vista Operating System on your before. Failure to activate within 30 days will result in your computer going into a Reduced Functionality Mode(RFM). Use the method outlined below which you can use upto 3 times to delay Windows Vista Activation and reset Vista’s Activation Clock. In other words you get to try Windows Vista for upto 120 days (30 days original + 3 time delay) without the need to activate your license for Windows Vista
Note: This is not an illegal crack for Windows Vista.
Open Command prompt in Windows Vista by pressing <Windows key> + R and type in cmd.exe
At the command prompt type in the following command
c:\> cd windows\system32
c:\windows\system32> sysprep /generalize