I downloaded ubuntu 13.10 amd64 iso and used all of following methods to make a install media. UNetBootin Universal USB installer (from windows) But I cannot boot from USB pen drive. Some time it just drop me in grub menu of previously installed ubuntu 13.04. Sometime it show a message "Could not open //fallback.efi: 14 ..." for a moment and then just stays there(blank screen). How to boot from USB pen drive?