Here is a tutorial for installing Windows 8 without a bootable device including CD, DVD, or USB.
The procedure is to install Windows 8 operating system onto the another partition, without any bootable device.
How To Install Windows 8 Without A Bootable Device:
STEP 1: Download the Microsoft ISO file from here. A Windows 8 ISO image would be downloaded to Your PC.
STEP 2: Then mount the file using a mounting tool like I used Daemon Tools lite to mount this ISO file.(As given in the image below).
STEP 3: Now, open the ISO file with a mounting tool and explore the ISO file.
STEP 4: Now, go to the folder named as “Sources”.
STEP 5: Click on Setup.exe and run it.
STEP 6: Setup will start install temporary files to your PC, Then you have to re-start your PC.
Follow further instructions as if installing Windows 7.
Enjoy the new metro interface Windows 8 operating system for your PC. Go ahead and try out yourself. Also, check out our post on Boot Windows 7 To Windows 8.