Hi sorry for late reply to your post but my PSU failed a short while back a tell tale sign is 2 vertical lines on the display panel.
Got a new one from H M sat in Germany.
Does it keep rebooting with a green screen? ,if yes there should be a crashlog on the hdd. Post that on the forum so people can see whats going wrong at your box.
No blue screen just starts to boot then clicks and starts all over.