Hi Nev
Couldnt log in once I logged out so re-registered.
I had a spare power supply from the kids old pc and it was 350w like the one I am having problems with, so tried that, but again the pc powered up and down as before and when I decided to try the first power supply again, with fingers crossed, nothing at all happened the pc would not boot up.
The usb card was a generic 6 port card.
Regards
Nick