How to install Windows 8 without the setup DVD that came with my notebook? [duplicate]

Use a clean Windows 8 DVD or MSDN/Technet ISO. This DVD detects the OEM Key which is now embedded to the BIOS:

http://blogs.technet.com/b/keithcombs/archive/2012/11/16/windows-8-bios-keys-embedded-goodness.aspx

If you look at the bottom of my machine, you’ll notice there is no Windows 8 Certificate of Authenticity (COA). There is an official Windows 8 logo sticker, but no product key.

The good news is that you no longer have to worry about it fading or getting scratched. The 5x5 key is embedded in the BIOS. Therefore all I had to do in order to install a fresh clean copy of Windows 8 was attach an external DVD drive, boot from the retail DVD, and run setup. As soon as I connected to the internet, the machine activated. It never asked me for a key. No fuss!!!