When it does start it get a very short buzzing sound coming from the power supply.
Also, whilst it was running, it blue screened once and when it reloaded the gui in my software was going a little strange, with thin lines appearing through the menu titles (disappearing when moved curser over) and the close down symbol (x) appearing twice, one on top of the other.
I took it to my local pc shop and found out that the guy who bulit it had put it in upside down so the fan was at the bottom of the case (its an inverted case).
My power supply was a Corsair AX850 and i have replaced it with the same one.
I just hope my other components haven't been damaged, although the guy at the shop said that it was highly unlikely, as i have an Asus Sabretooth X79 motherboard and he says that they are hard to damage.