Hi there
Have you tried making a USB bootable image (instructions in the Forum) and then boot from that.
Incidentally I should download a tool such as GPARTED as well (Stand alone bootable Partition manager) - so you can correctly re-format the disks in case of an install failure. The W8 install process often creates a small 100MB partition (system partition) which needs to be set as ACTIVE otherwise system won't boot. Windows install should do this but I'd suggest the following :
1) create bootable USB install from your ISO.
2) download bootable version of GPARTED
3) re-format your HDD. (Boot GPARTED and follow the simple instructions the GUI is fine).
4) boot from the USB and install.
You'll need to get into the BIOS to set the machine to boot from the USB device -- BIOS usually enabled by EITHER Del/F2/F8 key --depends on your computer.
(During the install the computer will re-boot after it's copied the files to HDD -- usually that part takes around 5 - 10 mins --if that.
At this point before computer re-boots remove the install medium (USB or DVD) otherwise you can get totally hosed up.
Cheers
jimbo