Reinstalling preinstalled Windows 8 without Windows DVD
Probably this is nothing new, but I have spent almost one day to figure this out.
If you have a computer with preinstalled windows and want to do a clean install, the easies way is to go to http://windows.microsoft.com/
This has the advantage, that you can create it with EFI secure boot, which is fast and secure.
For Windows 7 you can use the following link: http://www.microsoft.com/en-us/software-recovery