The green light on the back is on when plugged in and the orange light on the motherboard is lit but there is no response of any sort when I press the power button on the front. the led on the power button does not light and there is no beeping. Is there anything that I can check to try and isolate the problem? What I have tried is shorting the PSU with a paper clip from the green wire to the adjacent black wire in the 24 pin plug and the PSU fan turned on. I am not a computer guy at all, does this mean that the PSU is ok and the motherboard is bad or is there other things I can check?