I installed Ubuntu 13.04 64bit as dual boot with Windows 8, UEFI enabled and SECUREBOOT disabled in bios. After the installation could not see any option to boot Ubuntu. Only windows 8 boots.
I also tried boot repair, please check the link I got during the boot repair completion: http://paste.ubuntu.com/6009260/
Please note, I have disable fast boot from Windows 8 power options.