I got my new cpu today and replaced the one already in the system. However, when I came to powering up the system, nothing happens. I thought I forgot to switch on the PSU at first so I check the rocker switch on the back, but still nothing. I think the PSU is still alive because this zip noise when I turn the rocker switch to the 'off' position (as it always have done). I do hear a really faint clicking noise when i put my ear right in the box, and have noticed a faint blinking light on the front panel (power LED). Can anyone help me here please?