I'm trying to install Ubuntu onto new built PC without an OS. I burned Ubuntu 14.04.1 Desktop AMD64 onto a disc and inserted that into the disk drive and set the boot priority to the disk drive first.
Now I will go through the boot process second by second for diagnostic purposes.
0 - 15: This: 
15 - 40: Purple square at top left of screen with black background.
40 - 100: Ubuntu loading screen: 
100 - indefinate: There's a purple square at the top left corner of the screen with a £ inside it. Underneath that, it says:
BusyBox v1.12.1 (Ubuntu 1:1.21.0-1ubuntu1) built-in shell(ash)
Enter 'help' for a list of built in commands.
(initramfs) Unable to find a medium containing a live file system