Microsoft has been focusing on Windows 8 for all of past year and the OS has definitely turned out to be great. Microsoft just released the Consumer preview of Windows 8 (Download Windows 8) to the public after the press conference at MWC 2012.
If you install the Windows 8 Consumer Preview using the installer provided by Microsoft, you will not require a product key. However, if you create a installation media and start your PC from media and then install Windows 8 consumer preview, you will require a product key.
The product key for installing Windows 8 Consumer Preview is:
Once again, you will only require this if you are using the ISO file and creating a bootable installer and installing Windows 8 using a USB drive or DVD.
If you install Windows 8 Consumer Preview using the Windows 8 Consumer Preview Setup program, you won’t need to enter a product key—the setup program automatically provides the product key. If you create installation media, start your PC from the media, and then install Windows 8 Consumer Preview.