I've put together a basic system.
I am trying to install Windows 7.
I have tried using a USB flash drive and a DVD - both same issue.
I have tried three hard drives and two different SATA cables.
Basically, when I boot from the USB flash drive/DVD, sometimes I get the "Windows is loading files..." progress bars before it reboots, sometimes it reboots as soon as I select to boot from the USB flash drive/DVD.
CPU temperature is at 37C/98F, MB temperature is at 23C/73F. i.e. both are fine.
BIOS is up-to-date.
EDIT: One of the two RAM sticks was faulty