Well ive got a new piece of information.
The voltage switch on the PSU was originally 230, (it should have been 115) and thats when everything was powering up like in my original post. When i flick the switch over to 115, the computer will not stay on. All of the fans will flicker for a split second but then the computer will fail to turn on.
Should the fan inside the PSU be on at all times while the computer is on? When it is at 230v, and all other fans are powered on, the PSU fan does nothing whatsoever. Could this be a sign of a faulty PSU?
I have tried different power cables and different power outlets to no avail.