I did have the old trick of shorting the green pin to an earth and both PSU
were running. I even checked all the cable ends with a voltmeter. 12.26v
and 5.1v on all Molex connectors and 12.26 on the PCI-e connectors so all
would seem well. I swapped them around this afternoon to try them out and
this gave me the chance to check everything out. My LCD Poster doesn't seem
to be fully displaying but with the GTX in place it was flashing between DET
DRAM and CPU INIT(that dreaded one) but no POST. I did notice the GTX fan
at full speed and the LED lit up green on the back of the card.
Hmmmmmmmmmmmmmmm!
I then swapped out some RAM but alas nothing changed. I then swapped out
the VGA cards again and all POSTed well except that the BIOS was at default
and displayed that error (BIOS ERR).
Now I'm stuck with a very expensive paperweight unless I can get another PC
without 680i or 780i chipsets.
I have now got everything running on one PSU (Hiper E880W) and I am planning
a BIOS update to see if this will help.

Thanks

Robin