in any event, gene
were you able to figure out the problem? sometimes car DC isn't the same as AC.
Revlis (the person who began this post) stated that his MOBO works fine with the ATX power supply - but when he hooks it up to opus - nothing.
I had so many problems with a DC power supply i gave up and got an inverter 1200 watts. i simply hook up my pc to that and all is fine. i find this is an alternative if you are not an expert with electronics such as myself...