Sorry to post a whole new topic, but wanted to grab your attention.
Thanks for that - it's a new box so I can take it back. I understand that the power switch has to connect to the motherboard and it might be my connections that are screwed up, but I reckon that when you switch on the power the fan on the PSU should go round even if the motherboard is dead - is that right or wrong ???
I still think I'm being a bit stupid but is there a way I can be sure whether it's the PSU before I march it back to the shop tommorrow ?